SEAL-U-CUP 3708587 - Caterpillar

MID 87 - Chassis ECMCID 429 - Steering Pump Oil Pressure SensorFMI 4 - Voltage Below 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 below normal.The pressure sensor is a PWM sensor. The PWM signal varies with the input pressure.The following can cause this code:
Sensor signal circuit shorted to ground
Sensor 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 4 is active before performing this procedure.Note: Use a calibrated digital multimeter for this procedure.Test Step 1. CHECK THE SENSOR
Turn on the disconnect switch and the key switch.
Observe the diagnostic code status.
Disconnect the sensor from the harness.
Observe the diagnostic code status.Expected Result:CID 429 FMI 4 remains active and has not changed.Results:
OK - CID 429 FMI 4 remains active and has not changed. Proceed to Test Step 2.
NOT OK - The diagnostic code is no longer active. The sensor has failed.Repair: Replace the sensor.STOPTest Step 2. CHECK THE GROUND
Turn off the key switch and the disconnect switch.
Disconnect the harness from the sensor.
Disconnect the harness connectors from the ECM.
At the harness connector for the ECM, measure the resistance from the signal contact J2-42 (wire C462-PK(Pink)) of the harness to all possible ground sources. Measure the resistance to all contacts of the harness connectors for the ECM.Expected Result:Each resistance is greater than 5000 ohms.Results:
OK - Each resistance is greater than 5000 ohms. Proceed to Test Step 3.
NOT OK - A resistance is not correct. There is a short between signal contact J2-42 (wire C462-PK(Pink)) and the circuit with the low resistance.Repair: Repair or replace the harness.STOPTest Step 3. CHECK DIAGNOSTIC CODE
Inspect the harness.Clean the harness connector contacts.Inspect the harness connector contacts for corrosion or damage.Inspect the wire insulation for damage caused by heat, corrosion, or chafing.
Perform a 45 N (10 lb) pull test on each circuit wire.
Reconnect all harness connectors.Verify that the connectors are fully seated and the clips are fastened.
Check for intermittent problems. Use Cat® Electronic Technician (Cat® ET) and perform a wiggle test on the harness.
Turn on the disconnect switch and the key switch.
Operate the machine.
Check CID 429 FMI 4 status.Expected Result:CID 429 FMI 4 is not active.Results:
OK - CID 429 FMI 4 is not active.Repair: The initial diagnostic code was probably caused by a poor connection at one of the connectors that was checked.Resume normal operation.STOP
NOT OK - CID 429 FMI 4 is active. The ECM may have failed.Repair: Exit this procedure and perform this procedure again. Contact the technical communicator at your Caterpillar dealer. If the ECM requires replacement, see Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOP