C13 and C15 Engines for Combat and Tactical Vehicles Caterpillar

Note: Valid only if engine is equipped with an intake valve actuator.

The Intake Valve Actuation system (IVA) uses pressurized engine oil to delay the closing of the intake valves. The system is controlled by the Engine Control Module (ECM). The system contains the following components:

Check Valve (3) - Pressurized engine oil flows to a rail inside the valve cover base. A check valve prevents oil from flowing from the rail back to the main oil gallery.

Pressure Sensor (2) - A pressure sensor is threaded into the rail. The sensor converts the rail pressure into an electrical signal. The ECM monitors the signal in order to determine the pressure of the oil in the rail.

Control Valve (1) - A control valve is threaded into the rail. The control valve contains a coil and a cartridge assembly. The cartridge assembly contains a spool. The spool is normally closed. When the spool is closed, the oil is contained in the rail. The ECM sends a signal to the coil in order to fully open the spool. The oil is released into the space underneath the valve cover and the rail pressure is reduced.

Actuator (4) - The actuators are located under the valve covers. Pressurized engine oil flows from the rail to each actuator. The actuators use the pressurized engine oil and electrical commands from the ECM in order to delay the closing of the intake valves.

Illustration 1	g01329056
Component location on a typical C11 or C13 engine (1) Control valve (2) Pressure sensor (3) Check valve (4) Actuators

Illustration 2	g01329140
Component location on a typical C15 engine (1) Control valve (2) Pressure sensor (3) Check valve (4) Actuators

System Operation During Engine Start

The ECM performs the following sequence of operations every time the engine is started:

• The ECM commands the control valve to open for 17 seconds.

• The ECM checks the temperature of the coolant.

• The ECM commands the control valve to close when the coolant temperature exceeds 20 °C (68 °F). This allows the temperature of the oil in the rail to warm up.

• The ECM commands the control valve to open. The ECM samples the rail pressure. The ECM commands the control valve to close. The ECM takes a second sample of the rail pressure. The ECM compares the two pressure values. The ECM activates a 283-7 code if the pressure difference is too low.

• The control valve should remain closed during engine operation.

System Operation During Engine Operation

The system does not operate until the engine has reached normal operating temperature.

Illustration 3	g01329143
Section view of the components (4) Actuator (5) Space (6) Solenoid (7) Piston (8) Rocker arm (9) Valve (10) Rail (11) Intake valves

Each actuator (4) contains two solenoids (6). Each solenoid is connected to a valve (9). The solenoid is normally de-energized. The valve is normally open. This allows oil to flow between rail (10) and the space (5) above piston (7).

Rocker arm (8) is down when the intake valves are open. Pressurized oil flows from rail (10) to space (5) above piston (7). This causes the piston to move down. The piston contacts rocker arm (8).

The ECM energizes solenoid (6) when the ECM requires intake valves (11) to remain open. The energized solenoid closes valve (9). This traps the oil in space (5). The trapped oil causes piston (7) and rocker arm (8) to remain down. This keeps intake valves (11) open.

The ECM de-energizes solenoid (6) when the ECM requires the intake valves to close. The de-energized solenoid lifts valve (9). Valve springs (9) raise intake valves (11), rocker arm (8), and piston (7). The piston forces the oil from space (5) into rail (10).

The flow of oil into the rail changes the pressure of the oil in the rail. The ECM monitors the rail pressure. The ECM determines if the changes in rail pressure are correct for the commands that were sent to a particular solenoid. The ECM activates a diagnostic code for the appropriate cylinder if the changes in rail pressure are incorrect for that solenoid.

Troubleshooting Procedure

Use this procedure to diagnose mechanical problems or electrical problems with the intake valve actuation system. The following diagnostic codes indicate that there is a mechanical problem or a electrical problem with the system:

Note: Resolve any electrical problems with the system before you use this procedure.

Symptoms

The following symptoms may occur if there is a problem with the intake valve actuation system.

• Intermittent check engine light

• Intermittent reductions in engine power

You may need to perform a road test in order to verify that the problem is resolved. If a road test is performed on the engine, the road test must be carried out under loaded conditions. The test must be performed at 75 percent of the engine's rated fuel rate for at least 30 seconds.

Check the box or fill in the appropriate answer in the appropriate section of each test step. Complete all of the pages. Return this information with the returned part and the troubleshooting guide. Ensure that the items are properly packaged in order to prevent damage during shipment.

If snapshots are available of the fault codes, provide a copy of the snapshots with the returned part. If snapshots are not available, please answer the following questions and return this sheet with the returned part.

• Engine serial number ________

• Dealer code ________

• Outside temperature at time of fault ________

• Engine coolant temperature at time of fault ________

• Fault codes that were present ________

Also, answer the following questions concerning the basic operating conditions:

• Did the fault occur immediately after the initial engine start-up ________

• Did the fault occur after the first heavy pull of the day ________

• Approximate time the faults started to occur after starting to drive (example: one hour or two hours after starting out) ________

• Approximate engine speed ________.

• Approximate fuel position ________.

Test Step 1. Check the Engine Oil Level

1. Stop the engine. Allow the engine to cool approximately 20 minutes so the oil level can stabilize.

2. Check the engine oil level.

Expected Result:

________Result 1 The engine oil level is "OK".

________Result 2 The engine oil level is low.

________Result 3 The engine oil level is high.

Results:

• RESULT 1 - The engine oil level is OK.

  Repair: Record the engine oil level. ________.

  Verify that the dipstick is calibrated correctly. Refer to Operation and Maintenance Manual, "Engine Oil Level Gauge - Calibrate".

  Proceed to Test Step 2.

• RESULT 2 - The engine oil level is low.

  Repair: Verify that the dipstick is calibrated correctly. Refer to Operation and Maintenance Manual, "Engine Oil Level Gauge - Calibrate".

  Add engine oil to the proper level.

  Record the amount of engine oil that was added. ________

  Road test the vehicle. Verify that the repair resolved the problem.

  If the problem has not been eliminated, proceed to Test Step 2.

• RESULT 3 - The engine oil level is high.

  Repair: Verify that the dipstick is calibrated correctly. Refer to Operation and Maintenance Manual, "Engine Oil Level Gauge - Calibrate".

  Record the amount of engine oil that was drained. ________

  Road test the vehicle. Verify that the repair resolved the problem.

  If the problem has not been eliminated, proceed to Test Step 2.

Test Step 2. Check the Engine Oil Pressure

1. Turn the keyswitch OFF.

2. Connect the Caterpillar Electronic Technician (ET) to the service tool connector.

3. Remove the engine oil pressure sensor. Install a tee in place of the sensor. Install the sensor and a mechanical pressure gauge into the tee.

4. Start the engine and allow the engine to warm up to operating temperature.

5. Monitor the status for "Engine Oil Pressure" on Cat ET while the engine is operated throughout the rpm range. Also check the value on the mechanical gauge.

6. Verify that the oil pressure is above the trip point in Illustration 4 or Illustration 5. Also, verify that the oil pressure is above the trip point in Table 2 or in Table 3.

7. Turn the keyswitch OFF.

C11 and C13 oil pressure table

Note: Does not apply to C13 engines for Combat and Tactical Vehicles.

Illustration 4	g01406093
C11 and C13 oil pressure map

Note: Does not apply to C13 engines for Combat and Tactical Vehicles.

C15 oil pressure table

Illustration 5	g01406096
C15 oil pressure map

Expected Result:

The engine oil pressure is above the "low oil pressure region".

Results:

• Yes - The engine oil pressure is above the "low oil pressure region" but below the "VVA" minimum pressure. Proceed to Test Step 4.

• Yes - The engine oil pressure is above the "low oil pressure region".

  Repair: Record the engine oil pressure. ________

  Record the engine rpm. ________

  Proceed to Test Step 3.

• No - The engine oil pressure is low.

  Repair: Record the engine oil pressure. ________

  Record the engine rpm. ________

  If there are any active diagnostic codes that are related to low oil pressure, refer to the appropriate topic in Troubleshooting, "Troubleshooting with a Diagnostic Code".

  If the oil pressure is constant throughout the rpm range, there is a problem with the circuit for the engine oil pressure sensor. Check the wire for the pressure sensor supply (terminal A) for an open circuit.

  If there are no diagnostic codes that are related to low oil pressure, refer to Testing and Adjusting, "Engine Oil Pressure - Test".

  Road test the vehicle in order to verify that the problem has been resolved.

  Proceed to Test Step 3.

Test Step 3. Determine the Logged Code

1. Turn the keyswitch ON.

2. Check for the following logged diagnostic codes:

   Note: Repair all electrical faults before troubleshooting the diagnostic codes that are listed below.

   • 283-7 Intake Valve Actuation Oil Pressure not responding

   • 385-1 Low Intake Valve Actuation System Oil Pressure

   • 285-7 through 290-7 Intake Valve Actuator not responding

Expected Result:

________Result 1 Diagnostic codes that have -5 or -6 fault code extensions are logged.

________Result 2 283-7 is logged.

________Result 3 385-1 is logged.

________Result 4 285-7 through 290-7 are logged.

Results:

• RESULT 1 - Diagnostic codes with -5 or -6 extensions are active or logged.

  Repair: Refer to Troubleshooting, "Intake Actuator Circuit - Test".

  STOP

• RESULT 2 - 283-7 is active or logged. Proceed to Test Step 4.

• RESULT 3 - 385-1 is active or logged. Proceed to Test Step 5.

• RESULT 4 - 285-7 to 290-7 are active or logged. Proceed to Test Step 8.

Test Step 4. Check the Control Valve

1. Turn the keyswitch OFF.

2. Disconnect the harness connector from the control valve. Carefully remove the control valve from the engine.
   Show/hide table

   Illustration 6	g01318034
   Holes on the side of the control valve

3. Refer to Illustration 6. Carefully wipe the oil from the holes on the side of the control valve.

4. Look for debris in the holes. Be sure to look at all of the holes.

   Note any debris that was found in the holes.________

   Note: If large amounts of debris are found, determine the source of the debris before you continue with this procedure.

   Remove the debris if the debris can be easily removed. Otherwise, replace the contaminated control valve with a new control valve.

5. Perform the following procedure in order to determine the position of the spool.
   Show/hide table

   Illustration 7	g01304628
   Positions of the spool When the valve is fully open, the spool blocks approximately 40 percent of the hole. (12) Spool

   1. Look through a hole in order to determine the position of spool (12). The spool should be fully closed. It may be necessary to use a penlight to determine the position of the spool.
      Show/hide table

      Illustration 8	g01304707
      Checking the position of the spool with a penlight (12) Spool (13) Penlight (14) Valve body

   2. Use penlight (13) to inspect valve body (14). Refer to Illustration 8. Press the end of the penlight against the valve body in order to fully illuminate the valve body. Illumination between valve body (14) and spool (12) indicates that the spool is not fully closed.

Expected Result:

The spool was not fully closed when the control valve was removed from the engine.

Results:

• Yes - The spool was not fully closed when the control valve was removed from the engine.

  Repair: Perform the following procedure:

  1. Replace the control valve.

  2. Clear all logged diagnostic codes.

  3. Start the engine and run the engine until the engine coolant temperature is at least 20 °C (68 °F).

  4. Look for a 283-7 diagnostic code.

  If the 283-7 diagnostic code does not return, return the engine to service. If the 283-7 diagnostic code returns, further testing is required in order to determine the root cause. Proceed to Test Step 6.

• No - The spool was fully closed when the control valve was removed from the engine. Further testing is required in order to determine the root cause. Proceed to Test Step 6.

Test Step 5. Test the Intake Valve Actuation Oil Pressure Sensor

An assembly will be used to regulate air pressure to the oil pressure sensor. Refer to Illustration 9. In addition to the assembly for regulating pressure, the technician will need a 146-4080 Digital Multimeter Gp and two 7X-1708 Multimeter Probes.

Illustration 9	g01329453
Typical example (28) Sensor connector (29) Intake valve actuation oil pressure sensor (30) Fabricated tool

The fabricated tool consists of the following fittings and components:

• 5/16 JIC Female to 1/4 JIC Male

• 1/4 JIC Female Swivel to 1/4 NPT Male

• 1/4 to 1/4 Male NPT

• Pressure regulator

Note: The technician is allowed to determine the exact assembly of this tool.

Illustration 10	g01946642
Intake valve actuation oil pressure sensor with an integral connector

Illustration 11	g01105023
Intake valve actuation oil pressure sensor that does not have an integral connector

1. Fabricate the above assembly.

2. Turn the keyswitch OFF.

3. Disconnect the connector for the intake valve actuation oil pressure sensor.

4. Remove the intake valve actuation oil pressure sensor from the valve cover base.

   Note: If this procedure is used on a C11 or C13 engine the valve cover must be removed.

5. Install the fittings and the pressure regulator onto the intake valve actuation oil pressure sensor.

6. Connect the connector for the intake valve actuation oil pressure sensor to the engine harness.

   Note: Ensure that the air pressure setting is less than 50 psi before applying air pressure onto the test apparatus.

7. Apply shop air pressure to the assembly.

8. Turn the keyswitch ON.

9. Determine if the sensor has an integral connector.

   1. Refer to Illustration 10 for a sensor with an integral connector. Measure the voltage between terminals "2" and "3" at the sensor connector.

   2. Refer to Illustration 11 for a sensor that does not have an integral connector. Measure the voltage between the terminals "B" and "C" at the sensor connector.

10. Apply the air pressure that is indicated in Table 4 to the intake valve actuation oil pressure sensor. Record the voltage measurements at the different air pressures.

Expected Result:

The voltage measurements are within the ranges listed in Table 4.

Results:

• OK - The voltage measurements are within range.

  Repair: Start the engine and allow the engine to run for at least 30 seconds once the engine coolant temperature is greater than 20 °C (68 °F). If the 283-7 code does not return, the repair is complete.

  If the 283-7 code recurs, proceed to Test Step 6. If a 385-1 code returns, proceed to Test Step 13.

• Not OK - The voltage measurements are not within the given range.

  Repair: Replace the intake valve actuation oil pressure sensor. Verify that the repair resolved the problem.

  STOP

Test Step 6. Perform a Leak Test

Review the following information before you perform the leak test.

It is normal for oil to flow from some locations during this test. The locations for oil flow on C11 and C13 engines are shown in Illustration 20. The locations for oil flow on C15 engines are shown in Illustration 22.

Illustration 12	g01329196
Actuator on a C11 or C13 engine. (15) Leak points near the solenoids (16) Purge orifice

Illustration 13	g01329207
Actuator on a C15 engine. (15) Leak points near the solenoids (16) Purge orifice

Leak Points Near the Solenoids - Clearances for moving hydraulic components may cause slight oil leakage from locations (15).

Purge Orifice - Purge orifice (16) allows air to purge from the actuator. The purge orifice is located on the bottom of some actuators. Oil should stream from each purge orifice during this test.

Oil should not flow from some locations. The following problems can cause oil to flow from these locations:

• Missing O-ring seal or damaged O-ring seal

• A component is loose

• A component has an internal failure

The locations where oil should not flow on C11 and C13 engines are shown in Illustrations 22, 23, and 24. The locations where oil should not flow on C15 engines are shown in Illustrations 25, 26, and 27.

Illustration 14	g01318017
Right rear view of a typical C11 and C13 engine (3) Check valve

Illustration 15	g01313365
Right rear view of the actuator for cylinders 5 and 6 on a typical C11 and C13 engine. An O-ring seal is installed at locations (17), (18), and (19). Location (19) applies to each actuator. (17) Plug threaded into rear of the rail (18) Joint between the valve cover base and the cylinder head (19) Joint between the actuator and the cylinder head

Illustration 16	g01313378
Right side view of the actuator for cylinders 1 and 2 on a typical C11 or C13 engine. An O-ring seal is installed at locations (19), (20), (21), and (22). Location (19) applies to each of the actuators. (19) Joint between the actuator and the cylinder head (20) Joint between the sensor and the valve cover base (21) Joint between the control valve and the valve cover base (22) Plug threaded into the front of the rail

Illustration 17	g01313403
Right side view of the rear of a typical C15 engine. Check valve (3) may be located at the top of the oil supply tube or at the bottom of the oil supply tube. (3) Check valve (23) Bottom of the tube for the oil supply to the rail

Illustration 18	g01317964
Top view of the right rear of a typical C15 engine. Two O-ring seals are installed at location (26) between quill tube (24) and jumper tube (25). One O-ring seal is installed at face seal (27) between jumper tube (25) and the valve cover base. Locations (26) and (27) apply to each of the actuators. (3) Check valve (24) Quill tube (25) Jumper tube (26) Joint between the quill tube and the jumper tube (27) Face seal between the jumper tube and the valve cover base

Illustration 19	g01317986
Right side view of the front of a typical C15 engine. An O-ring seal is installed at locations (20) and (21). (20) Joint between the sensor and the valve cover base (21) Joint between the control valve and the valve cover base (26) Joint between the quill tube and the jumper tube (27) Face seal between the jumper tube and the valve cover base

1. Turn the keyswitch OFF.

2. Disconnect the connectors for the speed timing sensors. This will prevent the engine from starting.

3. Disconnect the connector for the control valve. This will prevent the control valve from opening during the leak test.

4. Remove the valve covers.

5. Wipe all of the engine oil away from the following components:

   • Face seals for the intake valve actuators

   • Connection between the cylinder head and the valve cover base

   • Plugged ports on the intake valve actuators

   • Plugged ports on the valve cover base

   • The solenoids for the intake valve actuator

   Note: Do not crank the engine for more than 30 seconds.

   Note: It may be necessary to have a second person crank the engine while you check for leaks.

6. Crank the engine.

7. Check for oil leaks around all of the components under the valve cover.

8. Verify that all of the ports in the oil rail are plugged.

9. Verify that the oil flows through the purge orifice on the intake valve actuator.

Expected Result:

________Result 1 No leaks were detected.

________Result 2 No leaks were detected and no oil flowed through the purge orifice.

________Result 3 A leak was detected.

Results:

• RESULT 1 - No leaks were detected. Proceed to Test Step 7.

• RESULT 2 - No leaks were detected and no oil flowed through the purge orifice.

  Repair: Check the intake valve actuator system for debris that could restrict the flow of oil.

  STOP

• RESULT 3 - A leak was detected.

  Repair: Check the appropriate box that indicates the location of the leak.

  ________ Face seals for the intake valve actuators.

  ________ The intake valve actuation oil pressure solenoid.

  ________ The sealing joint that is between the cylinder head and the valve cover base.

  ________ Plugged ports on the intake valve actuators.

  ________ Plugged ports on the the valve cover base.

  ________ Intake valve actuators solenoids.

  Determine the source of the leak and repair the leak. Clear all logged diagnostic codes.

  Install the valve covers. Connect all electrical connectors.

  Start the engine if 283-7 was the only diagnostic code that was logged. Run the engine for at least 30 seconds until the engine coolant temperature is greater than 20 °C (68 °F). If 283-7 does not return, the repair is complete.

  If other diagnostic codes were logged, road test the vehicle. Some problems will only occur when the engine is under a load. If logged diagnostic codes do not return, the repair is complete.

  Proceed to Test Step 7.

Test Step 7. Check the Check Valve

Note: Do not perform this procedure on engines with serial numbers (S/N: KCA1-160; KCB1-508). Assume that the check valve is OK. Proceed to the results.

1. Remove the check valve.

2. Inspect the check valve. Look for debris that could cause the check valve to stick.

   List any debris that was found in the check valve. ________

   Note: If large amounts of debris are found, determine the source of the debris before continuing with this procedure.

Expected Result:

The check valve is OK.

Results:

• OK - The check valve is "OK". Proceed to Test Step 8.

• Not OK - The check valve is damaged.

  Repair: Replace the check valve. Verify that the repair has corrected the problem. If 283-7 was the only diagnostic code that was logged, start the engine and allow the engine to run for at least 30 seconds once the engine coolant temperature is greater than 20 °C (68 °F). Verify that the repairs have eliminated the problem. If 283-7 does not return, the repair is complete.

  If 283-7 returns or if 385-1 returns, proceed to Test Step 5. If 285-7 through 290-7 returns, proceed to Test Step 8.

Test Step 8. Perform the Automatic "Cylinder Cutout Test"

1. Start the engine.

2. Access the "Cylinder Cutout Test" in the "Diagnostic Tests" under the "Diagnostics" menu.

3. Select the "Automatic Cylinder Cutout Test" on Cat ET.

4. Start the test.

Expected Result:

All of the cylinders indicated "OK" during the "Cylinder Cutout Test".

Check the appropriate box in front of the cylinders that indicates "OK".

________ #1 cylinder

________ #2 cylinder

________ #3 cylinder

________ #4 cylinder

________ #5 cylinder

________ #6 cylinder

Results:

• OK - Proceed to Test Step 9.

• Not OK - One or more cylinders failed the "Cylinder Cutout Test".

  Repair: Diagnose the problem and then repair the cylinders that failed the "Cylinder Cutout Test" before continuing with this procedure. Clear all logged diagnostic codes. Verify that the repair has eliminated the problem in the cylinder.

  Proceed to Test Step 9.

Test Step 9. Perform the "Intake Valve Actuator Test"

Note: The "Intake Valve Actuator Test" is not valid until a "Cylinder Cutout Test" has shown all of the cylinders to be functioning properly.

1. Start the engine. Allow the engine to operate until the coolant temperature is at least 60 °C (140 °F).

2. Access the "Intake Valve Actuator Test" in the "Diagnostic Tests" under the "Diagnostic" menu.

3. After you adhere to the warnings, start the automatic "Intake Valve Actuator Test".

   Note: The test will cycle two times. Once the test is complete the engine speed will increase to 2100 rpm for 15 seconds. An "OK" or "Not OK" will be displayed once the test is complete.

Expected Result:

All cylinders indicate "OK" during the "Intake Valve Actuator Test".

Results:

• OK - All cylinders indicate "OK".

  Repair: Check the appropriate box in front of the cylinders that indicates "OK".

  ________ #1 cylinder

  ________ #2 cylinder

  ________ #3 cylinder

  ________ #4 cylinder

  ________ #5 cylinder

  ________ #6 cylinder

  Warm the engine until the engine coolant temperature reaches 75 °C (167 °F).

  Repeat the "Intake Valve Actuator Test".

  If all cylinders indicate "OK", proceed to Test Step 11.

• Not OK - One or more cylinders indicate "Not OK".

  Repair: Check the appropriate box in front of the cylinders that indicate "Not OK".

  ________ #1 cylinder

  ________ #2 cylinder

  ________ #3 cylinder

  ________ #4 cylinder

  ________ #5 cylinder

  ________ #6 cylinder

  Proceed to Test Step 10.

Test Step 10. Check the Lash Settings for the Intake Valve Actuator

1. Turn the keyswitch OFF.

2. Allow the engine to cool.

3. Remove the valve cover(s) from the engine.

4. Check the lash settings for the intake valve actuators. Refer to Testing and Adjusting for the proper procedure.

Expected Result:

The lash settings are within the specification.

Record the initial lash settings for each unit prior to adjustment. Also, record the current mileage and the mileage of the last lash setting for the intake valve actuators.

________ Current Mileage

________ Mileage at last Adjustment

________ #1

________ #2

________ #3

________ #4

________ #5

________ #6

Results:

• OK - The lash settings are within the specification. Proceed to Test Step 11.

• Not OK - The lash settings are not within the specification.

  Repair: Adjust the lash settings. Refer to Testing and Adjusting for the proper procedure. If the mileage between the lash adjustment intervals that are indicated above (current mileage minus the mileage of the last adjustment) exceeds the recommended interval, the root cause of the problem could indicate a lack of maintenance. Refer to Operation and Maintenance Manual, "Maintenance Interval Schedule". Verify that the repair eliminates the problem by repeating the "Intake Valve Actuator Test". If all cylinders indicate "OK", return the vehicle to the customer.

  If one or more cylinders indicate "Not OK" proceed to Test Step 11.

Test Step 11. Perform a Leak Test

Review the following information before you perform the leak test.

It is normal for oil to flow from some locations during this test. The locations for oil flow on C11 and C13 engines are shown in Illustration 20. The locations for oil flow on C15 engines are shown in Illustration 22.

Illustration 20	g01329196
Actuator on a C11 or C13 engine. (15) Leak points near the solenoids (16) Purge orifice

Illustration 21	g01329207
Actuator on a C15 engine. (15) Leak points near the solenoids (16) Purge orifices

Leak Points Near the Solenoids - Clearances for moving hydraulic components may cause slight oil leakage from locations (15).

Purge Orifice - Purge orifice (16) allows air to purge from the actuator. The purge orifice is located on the bottom of some actuators. Oil should stream from each purge orifice during this test.

Oil should not flow from some locations. The following problems can cause oil to flow from these locations:

• Missing O-ring seal or damaged O-ring seal

• A component is loose

• A component has an internal failure

The locations where oil should not flow on C11 and C13 engines are shown in Illustrations 22, 23, and 24. The locations where oil should not flow on C15 engines are shown in Illustrations 25, 26, and 27.

Illustration 22	g01318017
Right rear view of a typical C11 and C13 engine (3) Check valve

Illustration 23	g01313365
Right rear view of the actuator for cylinders 5 and 6 on a typical C11 and C13 engine. An O-ring seal is installed at locations (17), (18), and (19). Location (19) applies to each actuator. (17) Plug threaded into rear of the rail (18) Joint between the valve cover base and the cylinder head (19) Joint between the actuator and the cylinder head

Illustration 24	g01313378
Right side view of the actuator for cylinders 1 and 2 on a typical C11 or C13 engine. An O-ring seal is installed at locations (19), (20), (21), and (22). Location (19) applies to each of the actuators. (19) Joint between the actuator and the cylinder head (20) Joint between the sensor and the valve cover base (21) Joint between the control valve and the valve cover base (22) Plug threaded into the front of the rail

Illustration 25	g01313403
Right side view of the rear of a typical C15 engine. Check valve (3) may be located at the top of the oil supply tube or at the bottom of the oil supply tube. (3) Check valve (23) Bottom of the tube for the oil supply to the rail

Illustration 26	g01317964
Top view of the right rear of a typical C15 engine. Two O-ring seals are installed at location (26) between quill tube (24) and jumper tube (25). One O-ring seal is installed at face seal (27) between jumper tube (25) and the valve cover base. Locations (26) and (27) apply to each of the actuators. (3) Check valve (24) Quill tube (25) Jumper tube (26) Joint between the quill tube and the jumper tube (27) Face seal between the jumper tube and the valve cover base

Illustration 27	g01317986
Right side view of the front of a typical C15 engine. An O-ring seal is installed at locations (20) and (21). (20) Joint between the sensor and the valve cover base (21) Joint between the control valve and the valve cover base (26) Joint between the quill tube and the jumper tube (27) Face seal between the jumper tube and the valve cover base

1. Turn the keyswitch OFF.

2. Disconnect the connectors for the speed timing sensors. This will prevent the engine from starting.

3. Disconnect the connector for the control valve. This will prevent the control valve from opening during the leak test.

4. Remove the valve covers.

5. Wipe all of the engine oil away from the following components:

   • Face seals for the intake valve actuators

   • Connection between the cylinder head and the valve cover base

   • Plugged ports on the intake valve actuators

   • Plugged ports on the valve cover base

   • The solenoids for the intake valve actuator

   Note: Do not crank the engine for more than 30 seconds.

   Note: It may be necessary to have a second person crank the engine while you check for leaks.

6. Crank the engine.

7. Check for oil leaks around all of the components under the valve cover.

8. Verify that all of the ports in the oil rail are plugged.

9. Verify that the oil flows through the purge orifice on the intake valve actuator.

Expected Result:

________Result 1 No leaks were detected. Oil flowed through the purge orifice.

________Result 2 No leaks were detected and no oil flowed through the purge orifice.

________Result 3 A leak was detected.

Results:

• RESULT 1 - No leaks were detected. Oil flowed through the purge orifice. Proceed to Test Step 12.

• RESULT 2 - No leaks were detected and no oil flowed through the purge orifice.

  Repair: Check the intake valve actuator system for debris that could restrict the flow of oil.

  STOP

• RESULT 3 - A leak was detected.

  Repair: Check the appropriate box that indicates the location of the leak.

  ________ Face seals for the intake valve actuators.

  ________ The intake valve actuation oil pressure solenoid.

  ________ The sealing joint that is between the cylinder head and the valve cover base.

  ________ Plugged ports on the intake valve actuators.

  ________ Plugged ports on the the valve cover base.

  ________ Intake valve actuators solenoids.

  Determine the source of the leak and repair the leak. Clear all logged diagnostic codes.

  Install the valve covers. Connect all electrical connectors.

  STOP

Test Step 12. Check the Check Valve

Note: Do not perform this procedure on engines with serial numbers (S/N: KCA1-160; KCB1-508). Assume that the check valve is OK. Proceed to the next Test Step.

1. Remove the check valve.

2. Inspect the check valve. Look for debris that could cause the check valve to stick.

   List any debris that was found in the check valve. ________

   Note: If large amounts of debris are found, determine the source of the debris before continuing with this procedure.

Expected Result:

The check valve is OK.

Results:

• OK - The check valve is OK. Proceed to Test Step 13.

• Not OK - The check valve is damaged.

  Repair: Replace the check valve. Road test the vehicle. Verify that the repair eliminates the problem.

  If the repair does not eliminate the problem, proceed to Test Step 13.

Test Step 13. Inspect the Hardware

Inspect the suspect intake valve actuator unit.

1. Remove the suspect intake valve actuator.

2. Inspect the face seal for damage.

3. Inspect the intake valve actuator for damage.

4. Check for debris in the intake valve actuator assembly. Do not disassemble the unit.

Expected Result:

The intake valve actuators are free of debris and the face seals are OK.

Results:

• OK - There is no debris in the assembly and the face seals are not damaged.

  Repair: Replace only the suspect intake valve actuator assembly. Refer to Testing and Adjusting for the proper procedure.

  Verify that the repair eliminates the problem by performing the "Intake Valve Actuator Test". Road test the vehicle. Some problems will only occur when the engine is under a load. Always road test the vehicle under a load before returning the vehicle to the customer.

  STOP

• Not OK - There is debris in the assembly or there is a damaged face seal.

  Repair: List any debris that was found in the assembly. ________

  Replace any damaged face seals. Remove any debris that is found in the intake valve actuator assembly. If the intake valve actuator failed the "Intake Valve Actuator Test", verify that the repair eliminates the problem by performing another "Intake Valve Actuator Test".

  If the intake valve actuator did not fail the "Intake Valve Actuator Test", perform a road test. Some problems will only occur when the engine is under a load.

  STOP