G3516 TA Engine Caterpillar

Use this procedure to troubleshoot a problem with the sensors. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.

Table 1

J1939 Code and Description	Comments
100-3 Engine Oil Pressure : Voltage Above Normal	The Electronic Control Module (ECM) detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
100-4 Engine Oil Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
107-3 Engine Air Filter 1 Differential Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
107-4 Engine Air Filter 1 Differential Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
108-3 Barometric Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
108-4 Barometric Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
109-3 Engine Coolant Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
109-4 Engine Coolant Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
1208-3 Engine Pre-filter Oil Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
1208-4 Engine Pre-filter Oil Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
4817-3 Engine Intake Manifold #1 Absolute Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
4817-4 Engine Intake Manifold #1 Absolute Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
5631-3 Engine Throttle Valve Differential Pressure : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
5631-4 Engine Throttle Valve Differential Pressure : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
5708-3 Engine Coolant Pressure #2 : Voltage Above Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.
5708-4 Engine Coolant Pressure #2 : Voltage Below Normal	The ECM detects signal voltage that is not in the acceptable range. The value of the parameter is set to a default value. The code is logged.

The ECM continuously creates a pull-up voltage on the signal wire for each sensor. The ECM uses this pull-up voltage to detect a problem in the signal circuit. When the ECM detects voltage that is above a threshold on the signal wire, the ECM activates a high voltage -3 diagnostic . When the ECM detects voltage that is below a threshold on the signal wire, the ECM activates a low voltage -4 diagnostic .

Note: There may be a delay of 30 seconds in order for Cat^® Electronic Technician (ET) to display an active diagnostic . When you check for a diagnostic , be sure to wait at least 30 seconds.

Table 2

Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Connect Cat® Electronic Technician (ET) to the service tool connector. B. Determine if a code is active or logged.	Codes	Result: A -3 code is active. Proceed to Test Step 2. Result: A -4 code is active. Proceed to Test Step 3.
2. Create a Short at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the sensor with the active -3 code. C. Install the jumper wire between the following terminals at the sensor connector: - Terminal 3 (signal) and Terminal 2 (sensor return) D. Connect Cat ET. E. Use Cat ET to monitor the following: - -4 code F. Turn the keyswitch to the OFF position.	Create a Short	Result: A -4 code did not become active. Proceed to Test Step 4. Result: A -4 code became active. Repair: The wiring harness is OK. Replace the sensor. Verify that the repair eliminated the problem.
3. Create an Open at the Sensor Connector A. Turn the keyswitch to the OFF position. B. Disconnect the sensor with the active -4 code. C. Connect Cat ET. D. Use Cat ET to monitor the following: - -3 code E. Turn the keyswitch to the OFF position.	Create an Open	Result: A -3 code did not become active. Proceed to Test Step 4. Result: A -3 code became active. Repair: The wiring harness is OK. Replace the sensor. Verify that the repair eliminated the problem.
4. Check the 5 VDC Supply Voltage at the Sensor Connector A. Turn the keyswitch to the ON position. B. Measure the voltage at the sensor connector between the following pins: - Pin 1 and Pin 2 C. Reconnect the sensor.	5.0 ± 0.2 VDC	Result: The supply voltage is 5.0 ± 0.2 VDC. Proceed to Test Step 5. Result: The supply voltage is not 5.0 ± 0.2 VDC. Repair:Repair or replace the wiring harness. If the problem is not resolved, proceed to Test Step 5.
5. Perform the Wiggle Test Carefully following this procedure is the best way to identify the root cause of an intermittent problem. A. Connect Cat ET. B. Use CAT ET to perform the following test: - "Wiggle Test" C. Slowly wiggle the wiring and the connectors between the P2 connector and the sensor. Pay particular attention to the wiring near each connector. Be sure to wiggle all the wiring. As you wiggle the wiring look for these problems: - Loose connectors or damaged connectors - Moisture on the connectors or the wiring - Damaged that is caused by excessive heat - Damage that is caused by chafing - Improper routing of wiring - Damaged insulation	Test	Result: The wiring failed the Wiggle Test. Repair: There is a problem with the wiring harness. Repair or replace the wiring harness. Verify that the repair eliminated the problem. Result: The wiring passed the Wiggle Test. Repair: The problem may be intermittent. Inspect the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information. If the wiring looks OK, perform the following procedure: 1. Turn the keyswitch to the OFF position. 2. Disconnect the connectors. Carefully inspect the terminals for proper installation. Make sure that each terminal is clean and dry. 3. Insert a pin into each socket. Verify that each socket grips the pin firmly. Repair any problems. 4. Connect all connectors. 5. Verify that the repair eliminated the problem.

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).