KNOB-CONTROL 3566069 - Caterpillar

Illustration 1 g01450393
Connections of the +8 volt sensor supplies
This diagnostic code is recorded when the ECM reads the voltage of the sensor supply circuit as higher than normal.Possible causes of this diagnostic code are listed:
The output of sensor supply has shorted to the + battery circuit.
The ECM has failed. This is unlikely.Note: Before performing this procedure, inspect the harness connectors that are involved in the circuit. Poor connections can often be the cause of a problem in an electrical circuit. Verify that all connections in the circuit are clean and secure. Verify that all connections in the circuit are in good condition. If a problem with a connection is found, correct the problem and verify that this diagnostic code is active before performing this procedure. The following test procedure may cause other diagnostic codes to be activated. Ignore these created diagnostic codes and clear the diagnostic codes when the problem has been corrected.Test Step 1. CHECK THE VOLTAGE AT A COMPONENT
Turn the disconnect switch and the key start switch to the ON position.
Disconnect the machine harness connector from one of the sensors in Illustration 1.
At the harness connector for the sensor, measure the voltage from contact A (wire C985-BU(Blue)) to contact B (wire 298-BK(Black)). Expected Result:The voltage measurement is 8.0 0.3 VDC.Results:
OK - The voltage measurement is 8.0 0.3 VDC. The voltage is correct. Proceed to Test Step 4.
NOT OK - The voltage measurement is greater than 8.0 0.3 VDC. The measurement is not correct. Proceed to Test Step 2.Test Step 2. CHECK THE POWER SUPPLY AT THE ECM
Turn the disconnect switch and the key start switch to the OFF position.
At the J1 connector for the ECM, use a wire removal tool to remove contact J1-44 (wire C985-BU(Blue)) and contact J1-45 (wire 298-BK(Black)) from the J1 connector. The machine harness connector J1 remains connected to the ECM.
Turn the disconnect switch and the key start switch to the ON position.
Use the multimeter probes in order to make contact on the connector pins. Measure the voltage at the ECM pins between the contact J1-44 and contact J1-45. Expected Result:The voltage measurement is 8.0 0.3 VDC.Results:
OK - The voltage measurement is 8.0 0.3 VDC. The voltage is correct. The ECM power supply is correct. Install the wires and sockets that were removed from the J1 connector back into the original locations. Proceed to Test Step 3.
NOT OK - The voltage measurement is greater than 8.0 0.3 VDC. The ECM power supply is not correct. The ECM has failed.Repair: Prior to replacing an ECM, always contact your dealership's Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the ECM requires replacement, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".STOPTest Step 3. CHECK FOR A SHORT CIRCUIT IN THE MACHINE HARNESS
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness connectors from the sensors in Illustration 1.
Disconnect the machine harness connectors J1 and