No Response From Engine Control Module (SCI Only) - Diesel

NO RESPONSE FROM ENGINE CONTROL MODULE (SCI ONLY) - DIESEL

No Response From Engine Control Module (SCI Only) - Diesel:

POSSIBLE CAUSES
- (D21) SCI transmit circuit shorted to ground
- (D20) SCI receive circuit shorted to ground
- (D21) SCI transmit circuit shorted to voltage
- (D20) SCI receive circuit shorted to voltage
- (D21) SCI transmit circuit open
- (D20) SCI receive circuit open
- (D21) SCI transmit circuit shorted to the (D20) SCI receive circuit
- Engine control module

Diagnostic Test

1. CHECK ENGINE CONTROL MODULE POWER AND GROUND
Perform the symptom Checking ECM Power and Ground Circuits. Checking the ECM Power and Grounds

Q: Did the vehicle pass this test?

YES: Go To 2
NO: Repair as necessary. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1

2. SCI CIRCUITS SHORTED TO GROUND




Turn the ignition off.
Disconnect the DRB from the DLC.
Disconnect the Engine Control Module C2 harness connector.
Measure the resistance between ground and the (D21) SCI Transmit circuit.
Measure the resistance between ground and the (D20) SCI Receive circuit.

Q: Is the resistance below 10.0 ohms for either circuit?

YES: Repair the SCI Circuit that measured below 10.0 ohms for a short to ground. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 3

3. SCI CIRCUITS SHORTED TO VOLTAGE




Turn the ignition on.
Measure the voltage of the (D21) SCI Transmit circuit.
Measure the voltage of the (D20) SCI Receive circuit.

Q: Is the voltage above 1.0 volt for either circuit?

YES: Repair the SCI Circuit that measured above 1.0 volt for a short to voltage. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4

4. (D21) SCI TRANSMIT CIRCUIT OPEN




Turn the ignition off.
Measure the resistance of the (D21) SCI Transmit circuit between the ECM harness connector and the DLC.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the (D21) SCI Transmit circuit for an open. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1

5. (D20) SCI RECEIVE CIRCUIT OPEN




Measure the resistance of the (D20) SCI Receive circuit between the ECM harness connector and the DLC.

Q: Is the resistance below 5.0 ohms?

YES: Go To 6
NO: Repair the (D20) SCI Receive circuit for an open. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1

6. (D21) SCI TRANSMIT CIRCUIT SHORTED TO THE (D20) SCI RECEIVE CIRCUIT




Measure the resistance between the (D21) SCI Transmit and the (D20) SCI Receive circuits.

Q: Is the resistance below 5.0 ohms?

YES: Repair the (D21) SCI Transmit circuit for a short to the (D20) SCI Receive circuit. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Replace the Engine Control Module. Perform POWERTRAIN VERIFICATION TEST - VER 1 (DIESEL). Powertrain Verification Test - Ver 1