SPRING 2384695 - Caterpillar

Illustration 1 g02319057
Transmission/Chassis ECM voltage connections
This diagnostic code is associated with the Transmission/Chassis ECM supply voltage. The FMI 04 diagnostic code means that the ECM has detected the voltage is below 19.0 VDC.The possible causes of this diagnostic code are listed below:
An open or poor ground circuit connection
An open or poor voltage supply connection
Charging system component failure
ECM failure, however ECM failure is unlikelyNote: Before performing this procedure, verify that all circuit breakers and fuses in the charging circuit and ECM supply circuit are closed. If a problem with a circuit breaker or 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 TRANSMISSION/CHASSIS ECM
Turn the keyswitch and disconnect switch to the OFF position.
At the J1 harness connector for the ECM, insert a 7X-1710 Multimeter Probe along the positive battery contact, J1-31 (wire 126-RD(Red)). Use the other multimeter probe to contact to frame ground.
Turn on the disconnect switch.
Start the engine and run at half throttle.
Measure the voltage between contact J1-31 (wire 126-RD(Red)) and frame ground.
At the J1 harness connector for the ECM, insert the 7X-1710 Multimeter Probe along 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 voltages are approximately the same and are 19 to 32 VDC.Results:
OK - Voltages are approximately the same and are 19 to 32 VDC. Proceed to Test Step 6.
NOT OK - Voltages are approximately the same, but are less than 19 VDC. Proceed to Test Step 4.
NOT OK - The voltage from the positive battery contact to frame ground is 8 to 32 VDC. However, the measurement between the ECM positive battery contact and the ECM negative battery contact is not in 8 to 32 VDC. The ground circuit may have failed. Proceed to Test Step 2.Test Step 2. CHECK THE GROUND CIRCUIT
Turn off the keyswitch and disconnect switch.
Disconnect the harness J1 connector from the ECM.
At the J1 harness connector for the ECM, measure the resistance between each negative battery contacts and frame ground. The contacts for the negative battery connections are shown in Illustration 1. Expected Result:Each resistance is less than 5.0 ohms.Results:
OK - Each resistance is less than 5.0 ohms. Proceed to Test Step 3.
NOT OK - A resistance is greater than 5.0 ohms. There is an open or poor connection in the ECM ground circuit (wire A202-BK(Black)).Repair: Check ground wire A202-BK(Black) at the rear frame. Ensure that the ground connection is clean, tight, and in good condition. Check all of the ground circuit connectors and splice points. Ensure that all connections are clean, secure, and in good condition. Repair or replace the harness.STOPTest Step 3. CHECK THE SUPPLY CIRCUITSThe keyswitch and disconnect switch remain off. The harness J1 connector remains disconnected from the ECM.
At the J1 harness connector for the ECM, using a jumper wire, measure the resistance between the alternator "B" terminal (wire 101-RD(Red)) and each positive battery contacts that are connected