SEAL-U-CUP 3708586 - Caterpillar

MID 87 - Chassis ECMCID 429 - Steering Pump Oil Pressure SensorFMI 3 - Voltage Above Normal
Illustration 1 g01832393
Steering pump oil pressure sensor circuit
This diagnostic code indicates that the "Chassis ECM" detects the steering pump oil pressure sensor voltage is above normal.The pressure sensor is a PWM sensor. The PWM signal varies with the input pressure.The following can cause this code:
Power circuit failure
Ground circuit failure
Sensor failure
Open sensor signal circuit
Harness failure
ECM failureNote: The following test procedure may create other diagnostic codes. Ignore these created codes and clear these created codes after the original diagnostic code has been corrected. Ensure diagnostic code CID 429 FMI 3 is active before performing this procedure.Note: Use a calibrated digital multimeter for this procedure.Test Step 1. CHECK FOR POWER AT THE SENSORDo not disconnect the harness connector from the sensor.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the voltage supply wire (contact A).
Turn on the disconnect switch and the key switch.
Measure the voltage from contact A to frame ground.Expected Result:The voltage is 24 VDC.Results:
OK - The voltage is 24 VDC. Proceed to Test Step 2.
NOT OK - The voltage is not 24 VDC. The circuit is open. The sensor fuse may have failed.Repair: Check the sensor fuse. Replace the fuse if the fuse has no continuity.Proceed to Test Step 4 if the fuse is good.Test Step 2. CHECK FOR SENSOR GROUNDThe harness remains connected to the sensor.
Turn off the key switch and the disconnect switch.
Remove the 7X-1710 Multimeter Probe from voltage supply wire (contact A).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along ground wire (contact B).
Measure the resistance from contact B to frame ground.Expected Result:The resistance is less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. Proceed to Test Step 4.
NOT OK - The resistance is greater than 5 ohms. The circuit is open.Repair: Replace or repair the harness.STOPTest Step 3. CHECK THE SENSOR OUTPUTThe key switch and the disconnect switch remain in the off position.
Reconnect the connectors.
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the signal wire (contact C).
At the back of the harness connector for the sensor, insert a 7X-1710 Multimeter Probe along the ground wire (contact B).
Turn on the disconnect switch and the key switch.
Measure the sensor signal.Expected Result:The sensor signal is as described at the beginning of this procedure.Results:
OK - The sensor signal is valid. Proceed to Test Step 4.
NOT OK - The sensor signal is not valid. The sensor has failed.Repair: Replace the sensor.STOPTest Step 4. CHECK THE HARNESS FOR AN OPENThe key switch and the disconnect switch remain in the off position.
Disconnect the harness from the sensor.
At the harness connector for the sensor, connect a jumper wire between contact B and contact C.
Disconnect the harness connectors from the ECM.
At the harness connector for the ECM, measure the resistance between contact J2-42 (wire C462-PK(Pink)) and contact J2-63