BELT-SERPENTINE 5197379 - Caterpillar

Illustration 2 g00676466
ECM connector P1
Illustration 3 g00709606
ECM connector P2
Fabricate a jumper wire with pins at both ends.
Use the jumper wire to short P90:A (Digital Sensor +8 VDC) and P90:C (Decelerator Position) together.
Measure the resistance between P2:24 (Decelerator Position) and P1:35 (Digital Sensor +8 VDC).
Move the one end of the jumper wire from P90:A (Digital Sensor +8 VDC) to P90:B (Digital Return). Leave the other end in P90:C (Decelerator Position) together.
Measure the resistance between P2:24 (Decelerator Position) and P1:29 (Digital Return).
Remove the jumper wire and reconnect all of the connectors.Expected Result:The resistance should be less than 10 Ohms for each measurement.Results:
OK - The harness is good. Proceed to Test Step 8.
Not OK - There is an open circuit or excessive resistance in the harness or the connectors.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 8. Check the Signal Frequency and the Duty Cycle at the ECM
Illustration 4 g00676466
J1/P1 breakout
Illustration 5 g00709606
J2/P2 breakout
Install a 7X-1715 Adapter Cable (40 Pin Breakout) at ECM connector J1/P1.
Install a 7X-1715 Adapter Cable (40 Pin Breakout) at ECM connector J2/P2.
Turn the keyswitch to the ON position.
Measure the frequency and the duty cycle between P2:24 (Decelerator Position) and P1:29 (Digital Return) at the breakouts while you operate the decelerator.
Turn the keyswitch to the OFF/RESET position.Expected Result:The frequency should be between 150 and 1000 Hz. The duty cycle should be approximately 57 percent when the pedal is released. The duty cycle should be approximately 32 percent when the pedal is fully depressed.Results:
OK - A valid sensor signal is reaching the ECM. Proceed to Test Step 9.
Not OK - There is an intermittent problem in the wiring harness or the connectors.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 9. Check the Status on ET
Turn the keyswitch to the ON position.
Observe the status for "Decelerator Position" on ET while you operate the decelerator pedal.Expected Result:The status should read approximately 0 percent when the decelerator pedal is released. The status should progressively increase to 100 percent when the decelerator pedal is fully depressed.Note: This range can change depending on the adjustment of the decelerator pedal assembly.Results:
OK - The decelerator position sensor is working properly.Repair: Refer to Troubleshooting, "Electrical Connectors - Inspect" if the problem is intermittent.STOP
Not OK - A valid signal appears at the ECM, but the ECM is not reading the signal properly.Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.STOPTest Step 10. Check the Supply Voltage at the ECM
Illustration 6 g00676466
J1/P1 breakout
Install a 7X-1715 Adapter Cable (40 Pin Breakout) at ECM connector J1/P1.
Turn the keyswitch to the ON position.
Measure the voltage between P1:29 (Digital Return) and P1:35 (Digital Sensor +8 VDC) at the J1/P1 breakout.
Turn the keyswitch to the OFF/RESET position.Expected Result:The supply voltage should be 8.0 0.5 VDC.Results:
OK - There is an open circuit or excessive resistance in the harness between the ECM and the sensor.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOP
Not OK - The ECM does not appear to be producing the correct supply voltage.Repair: Troubleshoot