C1.7 and C2.2 Industrial Engine Caterpillar

Speed/Timing - Test

Usage:

C1.7 G34

This procedure covers the following diagnostic codes:

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Table 1
Diagnostic Codes for the Speed/Timing Sensors
J1939 Code	Code Description	Comments
4201-2	Engine Speed Sensor #1 : Erratic, Intermittent, or Incorrect	The Electronic Control Module (ECM) detects the following conditions: An intermittent loss of signal or a complete loss of signal from the primary speed/timing sensor for 2 seconds Engine speed at least 300 rpm for more than 0.5 seconds The warning light will come on and the diagnostic code will be logged. The ECM will use the signal from the secondary speed/timing sensor. The engine will be derated. If the signal from the secondary speed/timing sensor is also lost, the engine will stop.
4201-8	Engine Speed Sensor #1 : Abnormal Frequency, Pulse Width, or Period	The Electronic Control Module (ECM) detects the following conditions: An abnormal signal from the primary speed/timing sensor Engine speed at least 300 rpm for more than 0.5 seconds The warning light will come on and the diagnostic code will be logged. The ECM will use the signal from the secondary speed/timing sensor. The engine will be derated. If the signal from the secondary speed/timing sensor is also lost, the engine will stop.
723-2	Engine Speed Sensor #2 : Erratic, Intermittent, or Incorrect	The Electronic Control Module (ECM) detects the following conditions: An intermittent loss of signal or a complete loss of signal from the secondary speed/timing sensor for 2 seconds Engine speed at least 300 rpm for more than 0.5 seconds The warning light will come on and the diagnostic code will be logged. The ECM will use the signal from the primary speed/timing sensor. The engine will be derated. If the signal from the primary speed/timing sensor is also lost, the engine will stop.
723-8	Engine Speed Sensor #2 : Abnormal Frequency, Pulse Width, or Period	The Electronic Control Module (ECM) detects the following conditions: An abnormal signal from the secondary speed/timing sensor Engine speed at least 300 rpm for more than 0.5 seconds The warning light will come on and the diagnostic code will be logged. The ECM will use the signal from the primary speed/timing sensor. The engine will be derated. If the signal from the primary speed/timing sensor is also lost, the engine will stop.
Follow the troubleshooting procedure to identify the root cause of the fault.

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Illustration 1	g03838252
Speed/timing sensor locations (1) Primary speed/timing sensor (2) Secondary speed/timing sensor

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Illustration 2	g03838253
Speed/timing sensors (1) Primary speed/timing sensor (2) Secondary speed/timing sensor

The engine uses two engine speed/timing sensors. The primary speed/timing sensor is on the right-hand side of the flywheel housing. The primary speed/timing sensor generates a signal by detecting the movement of the holes around the rim of the flywheel. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM uses the signal from the speed/timing sensor to calculate the position of the crankshaft. The signal is also used to determine the engine speed.

The secondary speed/timing sensor is on the front of the timing case. The secondary speed/timing sensor generates a signal that is related to the camshaft position. The secondary speed/timing sensor detects the movement of fingers on the front of the fuel pump gear. The signal that is generated by the speed/timing sensor is transmitted to the ECM. The ECM calculates the speed and the rotational position of the engine by using the signal. The secondary speed/timing sensor is required for starting purposes.

During normal operation, the secondary speed/timing sensor is used to determine the cycle that the engine is on. When the timing has been established, the primary speed/timing sensor is then used to determine the engine speed and the angular position.

The loss of signal to the primary sensor and/or the secondary sensor will result in one of the following faults:

The engine will continue to run when only one sensor signal is present from either the primary sensor or the secondary sensor.
Loss of signal both sensors during operation of the engine will cause fuel injection to be terminated and the engine will stop.

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Illustration 3	g06010030
Schematic for the speed/timing sensors

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Illustration 4	g03838321
Pinouts for the primary speed/timing sensor (1) Primary speed signal - (2) Primary speed signal +

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Illustration 5	g03838413
Pinouts for the secondary speed/timing sensor (1) Secondary speed signal + (2) Sensor ground (3) +5 VDC

Complete the procedure in the order in which the steps are listed.

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Table 2
Troubleshooting Test Steps	Values	Results
1. Inspect Electrical Connectors and Wiring A. Turn the keyswitch to the OFF position. B. Inspect the connectors for the speed/timing sensors. Refer to Troubleshooting, "Electrical Connectors - Inspect". C. Perform a 45 N (10 lb) pull test on each of the wires in the suspect sensor connector and the sensor connections at the ECM. D. Check the ground connection on the ECM for abrasions and pinch points. E. Check the harness for abrasion and pinch points from the suspect sensor to the ECM. F. Check that the suspect sensor is installed correctly. Check that the suspect sensor is fully seated into the engine.	Loose connection or damaged wire	Result: There is a fault in a connector or the wiring. Repair: Repair any faulty connectors or replace the wiring harness. Ensure that all the seals are properly in place and ensure that the connectors are correctly coupled. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. Proceed to Test Step 2.
2. Check For Active Diagnostic Codes A. Turn the keyswitch to the OFF position. B. Connect the electronic service tool to the diagnostic connector. C. Turn the keyswitch to the ON position. If the engine will start, then run the engine. D. Use the electronic service tool to monitor active diagnostic codes or recently logged diagnostic codes. E. Turn the keyswitch to the OFF position.	Diagnostic codes	Result: Diagnostic code 4201-X is active or recently logged. Proceed to Test Step 3. Result: Diagnostic code 723-X is active or recently logged. Proceed to Test Step 8.
3. Inspect the Primary Speed/Timing Sensor A. Ensure that the sensor is correctly seated in the flywheel housing. Ensure that the retaining bolt is tightened to a torque of 5 N·m (44 lb in). Ensure that the sensor is not damaged. Replace a damaged sensor. Refer to Disassembly and Assembly, "Primary Engine Speed/Timing Sensor - Remove and Install". B. Turn the keyswitch to the ON position. If the engine will run, then run the engine. C. Use the electronic service tool to check if the 4201-X diagnostic code is still active.	Faulty sensor	Result: A 4201-X diagnostic code is no longer active. Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service. Result: A 4201-X diagnostic code is still active. Proceed to Test Step 4.
4. Check the Primary Speed/Timing Sensor A. Remove the primary speed/timing sensor. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install". B. Measure the resistance between pins 1 and 2 on the sensor.	109.5 Ohms to 143.5 Ohms	Result: The measured resistance is not within limits. Repair: Install a replacement primary speed/timing sensor. Refer to Disassembly and Assembly, "Crankshaft Position Sensor - Remove and Install". Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: The measured resistance is within limits. Proceed to Test Step 5.
5. Check the Wiring for an Open Circuit A. Remove the harness connector from the primary speed/timing sensor. B. Disconnect the engine interface connector. C. Disconnect the P2 connector from the ECM. D. Measure the following resistances: · Pin 1 on the sensor harness connector to pin 26 on the sensor side of the engine interface connector. · Pin 2 on the sensor harness connector to pin 11 on the sensor side of the engine interface connector. · Pin 26 on the ECM side of the engine interface connector to P2:43. · Pin 11 on the ECM side of the engine interface connector to P2:19.	Less than 2.0 Ohms	Result: A measured resistance is more than 2.0 Ohms. Repair: Repair or replace the wiring, as necessary. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: All measured resistances are less than 2.0 Ohms. Proceed to Test Step 6.
6. Check the Wiring for a Short Circuit A. Remove the harness connector from the primary speed/timing sensor. B. Disconnect the engine interface connector. C. Disconnect the P2 connector from the ECM. D. Measure the following resistances: · Pin 26 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 11 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 26 on the ECM side of the engine interface connector to all other pins on the connector. · Pin 11 on the ECM side of the engine interface connector to all other pins on the connector.	More than 1k Ohms	Result: A measured resistance is less than 1k Ohms. Repair: Repair or replace the wiring, as necessary. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: All measured resistances are more than 1k Ohms. Proceed to Test Step 7.
7. Check the Timing Holes Around the Flywheel A. Remove the primary speed/timing sensor. Refer to Disassembly and Assembly, "Primary Engine Speed/Timing Sensor - Remove and Install". B. Use a flashlight to check the timing holes around the flywheel for damage or blockage.	Timing marks damaged	Result: Blocked holes found on the flywheel timing marks. Repair: Clear the blocked holes or replace the flywheel. Refer to Disassembly and Assembly, "Flywheel - Remove" and Disassembly and Assembly, "Flywheel - Install". Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: Damage found on the flywheel timing holes. Repair: Repair or replace the flywheel. Refer to Disassembly and Assembly, "Flywheel - Remove" and Disassembly and Assembly, "Flywheel - Install". Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: No faults found. Contact the Dealer Solutions Network (DSN).
8. Measure the Supply Voltage at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the secondary speed/timing sensor. C. Turn the keyswitch to the ON position. D. Measure the voltage from terminal 3 on the sensor connector to engine ground.	4.5 VDC to 5.5 VDC	Result: The sensor supply voltage is not within the expected range. The fault is in the sensor supply wiring between the sensor and the ECM. Repair: Repair the faulty wiring or replace the faulty wiring. Use the electronic service tool to clear all logged diagnostic codes and verify that the repair eliminates the fault. Result: The sensor supply voltage is correct. Proceed to Test Step 9.
9. Inspect the Secondary Speed/Timing Sensor A. Ensure that the sensor is correctly seated in the front housing. Ensure that the retaining bolt is tightened to a torque of 5 N·m (44 lb in). Ensure that the sensor is not damaged. Replace a damaged sensor. Refer to Disassembly and Assembly, "Secondary Engine Speed/Timing Sensor - Remove and Install". B. Turn the keyswitch to the ON position. If the engine will run, then run the engine. C. Use the electronic service tool to check if the 723-X diagnostic code is still active.	Faulty sensor	Result: A 723-X diagnostic code is no longer active. Use the electronic service tool to clear all logged diagnostic codes. Return the engine to service. Result: A 723-X diagnostic code is still active. Proceed to Test Step 10.
10. Check the Wiring for an Open Circuit A. Remove the harness connector from the secondary speed/timing sensor. B. Disconnect the engine interface connector. C. Disconnect the P1 and P2 connectors from the ECM. D. Measure the following resistances: · Pin 1 on the sensor harness connector to pin 25 on the sensor side of the engine interface connector. · Pin 2 on the sensor harness connector to pin 10 on the sensor side of the engine interface connector. · Pin 3 on the sensor harness connector to pin 45 on the sensor side of the engine interface connector. · Pin 25 on the ECM side of the engine interface connector to P2:42. · Pin 10 on the ECM side of the engine interface connector to P2:18. · Pin 45 on the ECM side of the engine interface connector to P1:9.	Less than 2.0 Ohms	Result: A measured resistance is more than 2.0 Ohms. Repair: Repair or replace the wiring, as necessary. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: All measured resistances are less than 2.0 Ohms. Proceed to Test Step 11.
11. Check the Wiring for a Short Circuit A. Remove the harness connector from the secondary speed/timing sensor. B. Disconnect the engine interface connector. C. Disconnect the P1 and P2 connector from the ECM. D. Measure the following resistances: · Pin 25 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 10 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 45 on the sensor side of the engine interface connector to all other pins on the connector. · Pin 25 on the ECM side of the engine interface connector to all other pins on the connector. · Pin 10 on the ECM side of the engine interface connector to all other pins on the connector. · Pin 45 on the ECM side of the engine interface connector to all other pins on the connector.	More than 1k Ohms	Result: A measured resistance is less than 1k Ohms. Repair: Repair or replace the wiring, as necessary. Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: All measured resistances are more than 1k Ohms. Proceed to Test Step 12.
12. Check the Timing Fingers on the Fuel Pump Gear A. Remove the secondary speed/timing sensor. Refer to Disassembly and Assembly, "Secondary Engine Speed/Timing Sensor - Remove and Install". B. Use a flashlight to check the timing fingers on the timing plate on the fuel pump gear for damage.	Segments damaged	Result: Damage found on the fuel pump gear timing plate. Repair: Repair or replace the timing plate. Refer to Disassembly and Assembly, "Fuel Injection Pump Gear - Remove" and Disassembly and Assembly, "Fuel Injection Pump Gear - Install". Use the electronic service tool to clear all logged diagnostic codes and then verify that the repair has eliminated the fault. Result: No faults found. Contact the Dealer Solutions Network (DSN).