HEATER GP-JACKET WATER 3585220 - Caterpillar

Illustration 2 g01379576
Voltage Connections for the Transmission/Chassis ECM
This diagnostic code is associated with the system voltage of the machine that is supplied to the Transmission/Chassis ECM. The FMI 01 means that the ECM has detected that the system voltage is below normal. The ECM activates this diagnostic code when the system voltage is below 18.0 VDC.The possible causes of this diagnostic code are listed below:
An open circuit or a poor system ground circuit connection.
An open circuit or a poor connection in the voltage supply.
A charging system component has failed.
The ECM has failed. ECM failure is unlikely. Note: Before performing this procedure, verify that all circuit breakers and that all fuses in the charging circuit and the ECM system supply circuit are closed. If a problem with a circuit breaker or a fuse is found, correct the problem. Verify that this diagnostic code is active before performing this procedure. Test Step 1. CHECK SYSTEM VOLTAGE AT THE ECM
Turn the disconnect switch and the starter keyswitch to the OFF position.
At the J1 harness connector for the ECM, insert a 7X-1710 Multimeter Probe along the system power supply J1-31 (wire 126-RD(Red)). Use the other multimeter probe to make contact to frame ground.
Turn the disconnect switch to the ON position.
Start the engine and run the engine at half throttle.
Measure the voltage between contact J1-31 (wire 126-RD(Red)) and frame ground.
At the J1 harness connector for the Implement ECM, insert the 7X-1710 Multimeter Probe that was used for the frame ground contact along the system power supply negative battery contact J1-13 (wire A202-BK(Black)).
Measure the voltage between contact J1-31 (wire 126-RD(Red)) and contact J1-13 (wire A202-BK(Black)). Expected Result:Both voltage measurements are approximately the same and are in the range of 18.0 VDC to 32.0 VDC.Results:
OK - Each voltage measurement is approximately the same and is in the range of 18.0 VDC to 32.0 VDC. The system voltage is correct. Proceed to Test Step 6.
NOT OK - Each voltage measurement is approximately the same, however, the measurements are less than 18.0 VDC. The system voltage is below normal. Proceed to Test Step 4.
NOT OK - The measurement from the positive battery contact to frame ground is in the range of 18.0 VDC to 32.0 VDC, however, the measurement between the ECM positive battery contact and the ECM negative battery contact is not in the correct range. The ground circuit may have failed. Proceed to Test Step 2.Test Step 2. CHECK THE GROUND CIRCUIT
Turn the starter keyswitch and the disconnect switch to the OFF position.
Disconnect the machine harness J1 connector from the ECM.
At the J1 harness connector for the ECM, measure the resistance between each of the five negative battery contacts and frame ground. The contacts for the negative battery connections are illustrated in the connection diagram at the beginning of this procedure. Expected Result:Each resistance measurement is less than 5.0 ohms.Results:
OK - Each resistance measurement is less than 5.0 ohms. The ground circuit is correct. Proceed to Test Step 3.
NOT OK - One or more