SEAL-WIPER 3708596 - Caterpillar

MID 87 - Chassis ECMCID 429 - Steering Pump Oil Pressure SensorFMI 8 - Abnormal Frequency, Pulse Width, or Period
Illustration 1 g01832393
"Steering Pump Oil Pressure" sensor circuit
This diagnostic code indicates that the "Chassis ECM" detects an abnormal "Steering Pump Oil Pressure" sensor signal. The abnormality may be in frequency, pulse width, or period.The following can cause this code:
Sensor failure
Intermittent connections
ECM failureNote: Often, this diagnostic code is caused by an intermittent connection.Note: Ensure that there are no active CID 262 diagnostic codes for the 5 VDC sensor power supply before performing this procedure.Note: 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 8 is active before performing this procedure.Test Step 1. CHECK FOR POWER AT THE SENSOR
Disconnect the harness connector from the sensor.
Turn on the disconnect switch and the key switch.
At the harness connector for the sensor, measure the voltage between contact A (wire 113-OR(Orange)) and contact B (wire J879-GN(Green)).Expected Result:The voltage is approximately 24 VDC.Results:
OK - The voltage is approximately 24 VDC. Proceed to Test Step 3.
NOT OK - The voltage is not approximately 24 VDC. Proceed to Test Step 2.Test Step 2. CHECK THE POWER SUPPLY AT THE ECMThe J1 and J2 harness connectors are connected to the ECM.
Turn on the disconnect switch and the key switch.
At the harness connector of the ECM, insert the 7X-1710 Multimeter Probe into the back of the connectors at contacts J2-42 (wire C462-PK(Pink)) and J2-63 (wire J879-GN(Green)).
Measure the voltage.Expected Result:The voltage is 24 VDC.Results:
OK - The voltage is 24 VDC. There is a problem in the sensor circuit of the harness. Either supply wire C462-PK(Pink)or return wire J879-GN(Green)has a bad connection or open harness.Repair: See the machine Electrical Schematic.Determine the circuit that is open. Check the resistance of each circuit from the ECM connection to the sensor connection.Check each wire from connection point to connection point for an open.Repair or replace the harness.STOP
NOT OK - The voltage is not 24 VDC. 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".STOPTest Step 3. CHECK FOR A SHORTThe sensor remains disconnected from the harness.
Turn off the key switch and the disconnect switch.
Disconnect the J1 and J2 harness connectors from the ECM.
Measure the resistance between contact J2-42 (wire C462-PK(Pink)) and all contacts in 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 4.
NOT OK - A resistance is less than 5 ohms. There is a short between wire C462-PK(Pink)and the circuit with low resistance.Repair: Repair or replace the harness.STOPTest Step 4. CHECK THE SIGNAL CIRCUIT FOR AN OPEN IN THE HARNESSThe key switch and the disconnect switch remain in the off position.The harness connectors remain disconnected from the