F1845 Force TY-RAP

Illustration 1 g01234104
Schematic for the digital sensor supply
Test Step 1. Inspect the Electrical Connectors and the Wiring
Remove the electrical power from the ECM.
Illustration 2 g01234113
Typical left side view
(1) J1/P1 ECM connectors
Thoroughly inspect connector (1). Inspect the connectors for each digital sensor. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Illustration 3 g01234119
P1 ECM connector
(P1-4) +8 VDC
(P1-5) Return
(P1-66) Throttle position signal
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the digital sensor supply.
Check the torque of the allen head screws for the ECM connectors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".
Check the harness and wiring for abrasions and for pinch points from the battery 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:
041-03 8 Volt DC Supply short to +batt
041-04 8 Volt DC Supply short to groundExpected Result:One of the above diagnostic codes is active.Results:
Active 03 code - A 03 diagnostic code is active. Proceed to Test Step 3.
Active 04 code - A 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, "Troubleshooting Without a Diagnostic Code".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 the diagnostic functional test 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 sensor.
Restore the electrical power to the ECM.
Measure the voltage between terminals A and B at the harness connector for each sensor. Expected Result:Each voltage measurement is 8.0 0.4 VDC.Results:
OK - Each voltage measurement is 8.0 0.4 VDC.Repair: Connect the sensor connector. Clear all diagnostic codes. Check for active diagnostic codes. If the problem is intermittent, refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".STOP
Not OK - At least one voltage measurement 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. Disconnect the +8 V Digital Sensors and Check for Active Diagnostic Codes
Disconnect the throttle sensor.
Wait for 30 seconds after you disconnect the sensor. Look for the active 04 diagnostic code in order to deactivate. Expected Result:The 04 diagnostic code deactivates when the sensor is disconnected.Results:
OK - The 04 diagnostic code deactivates when the sensor is disconnected.Repair: Connect the suspect sensor. If the diagnostic code returns, replace the sensor.Connect the connector. Verify that the problem is resolved.STOP
Not OK - The 04 diagnostic code remains after the sensor is disconnected. Leave the sensor disconnected. Proceed to Test Step 5.Test Step 5. Check the +8 V Supply Wire for a Short Circuit
Remove the electrical power from the ECM.
Disconnect the J1/P1 and J2/P2connectors.
Verify that the digital sensor is disconnected. Note: Wiggle the harness during the following measurements in order to reveal an intermittent condition.
Measure the resistance between P1-4 (+8 V supply) and the remaining terminals on the P1 and P2 connectors.
Measure the resistance between P1-4 (+8 VDC supply) and the engine ground. Expected Result:Each check of the resistance indicates an open circuit.Results:
OK - Each check of the resistance indicates an open circuit. Proceed to Test Step 6.
Not OK - At least one check of the resistance does not indicate an open circuit. A +8 V supply wire has a problem. There may be a problem with a connector.Repair: Repair the wire and/or the connector, when possible. Replace parts, if necessary. Verify that the problem is resolved.STOPTest Step 6. Check the +8 V Supply and the Sensor Common for an Open Circuit
Install a jumper wire between terminals P1-4 (+8 V supply) and P1-5 (Return). Note: Wiggle the harness during the following measurement in order to reveal any intermittent short condition.
Measure the resistance between terminals A and B at the harness connector for each digital sensor.
Remove the jumper wire. Expected Result:Each resistance measurement is less than ten Ohms.Results:
OK - Each resistance measurement is less than ten Ohms. Proceed to Test Step 7.
Not OK - At least one resistance measurement is more than ten Ohms. A +8 V supply wire or a return wire has excessive resistance. There may be a problem with a connector.Repair: Repair the wires and/or the connector, when possible. Replace parts, if necessary. Verify that the problem is resolved.STOPTest Step 7. Check the +8 V Supply at the ECM
Remove terminal 4 from the P1 connector. Install a jumper wire with socket terminals on both ends into P1-4.
Remove terminal 5 from the P1 connector. Install a jumper wire with socket terminals on both ends into P1-5.
Connect the P1 connector.
Restore the electrical power to the ECM.
Measure the voltage between the jumper wires in P1-4 and P1-5.
Remove the electrical power from the ECM.
Restore all wiring to the original configuration. Expected Result: