CLIP 6D4246 - Caterpillar

System Operation Description:Use this procedure to troubleshoot any suspect problems with the following sensors:
Coolant temperature sensor
Fuel temperature sensor
Inlet manifold temperature sensor
Fuel outlet temperature sensorThis procedure covers the following diagnostic codes:
110-03 Engine Coolant Temperature open/short to +batt
110-04 Engine Coolant Temperature short to ground
172-03 Intake Manifold Air Temp open/short to +batt
172-04 Intake Manifold Air Temp short to ground
174-03 Fuel Temperature open/short to +batt
174-04 Fuel Temperature short to ground
1929-03 Fuel Return Temperature Sensor high/short to +batt
1929-04 Fuel Return Temperature Sensor low/short to groundThe troubleshooting procedures for the diagnostic codes of each temperature sensor are identical. The temperature sensors are passive sensors that have two terminals. The temperature sensors do not require supply voltage from the Electronic Control Module (ECM).
Illustration 1 g01175264
Schematic for engine temperature sensors
Test Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01175267
Left side engine view (typical engine view)
(1) Engine coolant temperature sensor
(2) Fuel temperature sensor
(3) Fuel outlet temperature sensor
(4) Inlet air temperature sensor
(5) J2/P2 ECM connector
Thoroughly inspect connector (5). Also, thoroughly inspect the connectors for temperature sensors (1), (2), (3), and (4). Refer to Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01150540
P2 terminals that are associated with the engine temperature sensors
(P2-18) Sensor return
(P2-32) Engine coolant temperature
(P2-33) Fuel temperature
(P2-34) Fuel outlet
(P2-35) Inlet air temperature
Illustration 4 g01146837
Harness connector for the temperature sensors
(1) Signal
(2) Return
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the temperature sensors.
Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and wiring for abrasions and for pinch points from each sensor to the ECM. Expected Result:All connectors, pins, and sockets are completely coupled and/or inserted. The harness and wiring are free of corrosion, of abrasion, and of pinch points.Results:
OK - The connectors and wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the wiring and/or the connectors. Replace parts, if necessary. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled.Verify that the repair eliminates the problem.STOPTest Step 2. Check for Active Diagnostic Codes
Connect Caterpillar Electronic Technician (ET) to the service tool connector.
Turn the keyswitch to the ON position.
Check for active diagnostic codes on Cat ET. Check and record any active diagnostic codes. Note: Wait at least 15 seconds in order for the diagnostic codes to become active.
Look for an -03 diagnostic code or an -04 diagnostic code. Expected Result:No diagnostic codes are active.Results:
OK - No diagnostic codes are active. The problem appears to be resolved.Repair: The problem may have been related to a faulty connection in the harness. Carefully reinspect the connectors and wiring. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.STOP
Not OK - An -04 diagnostic code is active at this time. Proceed to Test Step 3.
Not OK - An -03 diagnostic code is active at this time. Proceed to Test Step 4.Test Step