FRAME AS-UPPER 3157271 - Caterpillar

Illustration 1 g02555858
Connections of Supply Voltage Circuit for Transmission ECM
This diagnostic code is recorded when the system voltage is below 18 VDC. The brakes will be applied and the transmission will shift into neutral. The possible causes of this diagnostic code are listed below:
A charging system component has failed.
The wiring in the machine harness has failed.
The ECM has failed. The failure of the ECM is unlikely. Test Step 1. CHECK THE BATTERY VOLTAGE.
Start the engine and run at high idle for several minutes.
Measure the battery voltage at the battery posts. Expected Result:Battery voltage should be greater than 18 VDC. Results:
OK - Battery voltage is greater than 18 VDC. Battery voltage is correct. Proceed to Test Step 2.
NOT OK - Battery voltage is not greater than 18 VDC.Repair: The charging system is not correct. Check the charging system. See Special Instruction, REHS0354, "Starting and Charging System".STOPTest Step 2. CHECK THE SYSTEM VOLTAGE AT THE ECM.
The engine must still be running at high idle.
DO NOT DISCONNECT the machine harness from the ECM. At connector "J1" of the ECM, make a voltage measurement by using the multimeter probe.
At the machine harness for the ECM, insert the probe into the back of connector "J1". Measure the voltage between J1-39 (170-RD(Red)) and J1-70 (A273-BK(Black)). Expected Result:Voltage should be greater than 18 VDC. Results:
OK - Voltage is greater than 18 VDC. Battery voltage is correct. Proceed to Test Step 3.
NOT OK - Voltage is not greater than 18 VDC.Repair: The machine harness is not correct. Repair the machine harness or replace the machine harness.STOPTest Step 3. CHECK IF THE DIAGNOSTIC CODE REMAINS.
Inspect the harness connectors. Clean the contacts of the harness connectors and check the wires for damage to the insulation that is caused by excessive heat, corrosion, or chafing.
Perform a 45 N (10 lb) pull test on each of the wires that are associated with the circuit.
Reconnect all harness connectors in order to make sure that the connectors are fully seated. Also, make sure that the clips for each connector are fastened.
Turn the disconnect switch and the key start switch to the ON position.
Operate the machine.
Check the status of the diagnostic code. Expected Result:The diagnostic code is active.Results:
YES - The diagnostic code is active. The diagnostic code has not been corrected.Repair: The ECM has failed. Exit this procedure and perform this procedure again. Prior to replacing an ECM, always contact your dealership 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".STOP
NO - The diagnostic code is not active. The initial diagnostic code was probably caused by a poor connection at one of the harness connectors that was disconnected and reconnected. Resume normal machine operation.STOP