Alternator Load Signal Short To Ground

2271-ALTERNATOR LOAD SIGNAL SHORT TO GROUND

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
Continuously while the system is active.

- Set Condition:
The ECM is receiving a LIN bus error message.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Turn the ignition on.
With a scan tool, View DTCs.
Record all DTC information.
With a scan tool, Clear DTCs.
Start the engine and allow it to reach normal operating temperature.
Monitor the scan tool for at least 2 minutes.
With a scan tool, View DTCs.
Is the status Active for this DTC?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.

2. GLOW PLUG MODULE
Turn the ignition off.
Disconnect the Glow Plug Module harness connector.
Turn the ignition on.
With a scan tool, Clear DTCs.
With a scan tool, View DTCs.
Monitor the scan tool for at least 2 minutes.

NOTE: If the Glow Plug Module LIN bus circuit is shorted internally, the LIN Bus DTC will not set with the module disconnected. If the LIN bus is shorted to voltage or ground, or the Generator is internally shorted, this DTC will remain Active.

Is the status Active for this DTC?

Yes

- Go To 3

No

- Replace the Glow Plug Module.
- Perform the ECM Verification Test Ver. 1. Verification Tests

3. GENERATOR
Turn the ignition off.
Connect the Glow Plug Module harness connector.
Disconnect the Generator harness connector.
Turn the ignition on.
With a scan tool, Clear DTCs.
With a scan tool, View DTCs.
Monitor the scan tool for at least 2 minutes.

NOTE: If the Generator LIN bus circuit is shorted internally, the LIN Bus DTC will not set with the Generator disconnected. If the LIN bus is shorted to voltage or ground, this DTC will remain Active.

Is the status Active for this DTC?

Yes

- Go To 4

No

- Replace the Generator.
- Perform the ECM Verification Test Ver. 1. Verification Tests

4. LIN BUS CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the Glow Plug Module harness connector.
Disconnect the Engine Control Module (ECM) harness connector.
Measure the resistance between ground and the LIN Bus circuit in the Generator harness connector.
Is the resistance above 1000 ohms?

Yes

- Go To 5

No

- Repair the LIN Bus for a short to ground.
- Perform the ECM Verification Test Ver. 1. Verification Tests

5. LIN BUS CIRCUIT SHORTED TO VOLTAGE
Remove the ASD Relay.
Connect a jumper wire between cavity 30 and cavity 87 of the ASD Relay Connector.
Turn the ignition on.
Measure the voltage of the LIN Bus circuit in the Generator harness connector.
Is there any voltage present?

Yes

- Repair the LIN Bus for a short to voltage.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Go To 6

6. ENGINE CONTROL MODULE (ECM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Glow Plug Module and the Engine Control Module (ECM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the ECM Verification Test Ver. 1. Verification Tests

No

- Replace the Engine Control Module (ECM).
- Perform the ECM Verification Test Ver. 1. Verification Tests