CYLINDER HEAD GP 4N2622 - Caterpillar

System OverviewThe sensor signal for the passive sensor is routed from the ECM to terminal 1 of each sensor connector. The sensor return for the passive sensors is routed from the ECM to terminal 2 of each sensor connector.Diagnostics on the Caterpillar Electronic Technician (ET)Wiggle Test - The Wiggle Test allows you to monitor the status of the signals from the sensors.For additional information regarding the Wiggle Test, refer to the documentation that accompanies the Cat ET software.
Illustration 1 g02175198
Schematic for the passive sensors
Illustration 2 g02175299
Terminal locations at the P1 ECM connector for the passive sensors
(P1-3) Return
(P1-5) Return
(P1-16) Engine oil temperature
(P1-17) Air inlet temperature
Illustration 3 g02134161
Terminal locations at the P2 ECM connector for the passive sensors
(P2-17) Return
(P2-30) Return
(P2-56) Intake manifold air temperature (right side)
(P2-62) NRS temperature
(P2-83) Return
(P2-84) Engine coolant temperature
(P2-95) Intake manifold air temperature (left side)
(P2-96) Fuel temperature
Illustration 4 g01155187
Terminal locations at the connector for the passive analog sensors
(Terminal 1) Sensor signal
(Terminal 2) Sensor return Test Step 1. Check for Diagnostic Codes
Connect Cat ET to the service tool connector.
Restore electrical power to the ECM.
Start the engine.
Access the "Active Diagnostic Code" screen on Cat ET. Note: The engine must be running for seven minutes in order for a 110-3 code to become active.
Look for these active codes or logged codes:
-3
-4Results:
Logged Code - A diagnostic code is logged. Proceed to Test Step 4.
Active -3 - A -3 diagnostic code is active. Proceed to Test Step 2.
Active -4 - A -4 diagnostic code is active. Proceed to Test Step 3.Test Step 2. Create a Short at the Sensor Connector
Remove electrical power to the ECM.
Disconnect the suspect sensor.
Install the jumper wire between terminal 1 (sensor signal) and terminal 2 (sensor return) at the sensor connector.
Restore electrical power to the ECM.
Monitor the diagnostic codes on Cat ET. Check for an active -4 diagnostic code for the suspect sensor. Note: The engine must be running for seven minutes in order for a 110-3 code to become active.
Remove electrical power to the ECM. Results:
Active -3 - The -3 diagnostic code remains active for the suspect sensor.Repair: There is an open in the harness. Repair the wiring or replace the harness.Verify that the problem is resolved.STOP
Active -4 - A -4 diagnostic code became active after creating the short at the sensor connector.Repair: The wiring is OK. Replace the sensor.Verify that the problem is resolved.STOPTest Step 3. Create an Open at the Suspect Sensor Connector
Remove electrical power to the ECM.
Disconnect the sensor connector of the suspect sensor with the active -4 diagnostic code.
Restore electrical power to the ECM.
Monitor the diagnostic codes on Cat ET. Check for an active -3 diagnostic code for the suspect sensor. Note: The engine must be running for seven minutes in order for a 110-3 code to become active.
Remove electrical power to the ECM. Results:
Active -4 - The -4 diagnostic code remains active for the suspect sensor.Repair: There is a short in the harness. Repair the wiring or replace the harness.Verify that the problem is resolved.STOP
Active -3 - A -3 diagnostic code became active after disconnecting the