COVER 4P0988 - Caterpillar

Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Illustration 2 g01208116
Left side view of the engine (1) J1/P1 ECM connectors
Thoroughly inspect connectors (1). Inspect the connectors for the throttle switch. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01209336
P1 ECM connector (P1-22) High throttle input (P1-23) Low throttle input
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the throttle switch.
Check the torque of the allen head screws for the ECM connectors. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasions and for pinch points from the throttle switch to the ECM.Expected Result:All of the connectors, pins, and sockets are completely coupled and/or inserted, and the harness and wiring are free of corrosion, of abrasion or of pinch points.Results:
OK - The connectors and the wiring are OK. Proceed to Test Step 2.
Not OK - There is a problem with a connector and/or the wiring.Repair: Repair the connector and/or the wiring. 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 problem is resolved.STOPTest Step 2. Check for Active Diagnostic Codes
Connect the Caterpillar Electronic Technician (ET) to the service tool connector. Refer to electronic troubleshooting Troubleshooting, "Electronic Service Tools".
Restore the electrical power to the ECM.
Observe the active diagnostic code screen on Cat ET. Wait at least 30 seconds so that any codes may become active. Look for these codes:
41-03
41-04 Expected Result:One of the above diagnostic codes is active.Results:
Active 41-03 code - A 41-03 diagnostic code is active. Proceed to Test Step 3.
Active 41-04 code - A 41-04 diagnostic code is active. Proceed to Test Step 4.
No active codes - None of the above codes are active.Repair: If any of the above codes are logged and the engine is not running properly, refer to troubleshooting without a diagnostic code Troubleshooting.If the engine is running properly at this time, there may be an intermittent problem in a harness that is causing the codes to be logged. Refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".STOPTest Step 3. Check the Voltage on the +8 V Supply Wire
Remove the electrical power from the ECM.
Disconnect the harness connector for the throttle switch.
Restore the electrical power to the ECM.
Measure the voltage between the wires for the suspect throttle input(s) to wire A287-BK.Expected Result:The voltage measurement of the suspect throttle input(s) is 8.0 0.4 VDC .Results:
OK - The voltage measurement of the suspect throttle input(s) is 8.0 0.4 VDC.Repair: Connect the connectors for the throttle switch. Clear all diagnostic codes. Check for active diagnostic codes. If the problem is intermittent, refer to diagnostic functional tests Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - The voltage measurement for one of the suspect throttle input(s) is not 8.0 0.4 VDC. There is a problem with the wiring or with the ECM. Proceed to Test Step 5.Test Step 4.