No Response From PCM (SCI Only) - JTEC

NO RESPONSE FROM PCM (SCI ONLY) - JTEC

No Response From PCM (SCI Only) - JTEC:

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

Diagnostic Test

1. CHECK POWERTRAIN CONTROL MODULE POWER AND GROUND
Perform the symptom Checking PCM Power and Ground Circuits. Symptom Related Diagnostic Procedures

NOTE: With the DRB in the generic scan tool mode, attempt to communicate with the PCM. If the DRB can communicate with the PCM in the generic scan tool mode, it may not be necessary to perform this step.

Q: Did the vehicle pass this test?

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

2. SCI CIRCUITS SHORTED TO GROUND




Turn the ignition off.
Disconnect the DRB from the DLC.
Disconnect the Powertrain Control Module C3 harness connector.
Measure the resistance between ground and the (D21) SCI Transmit (PCM) circuit.
Measure the resistance between ground and the (D20) SCI Receive (PCM) 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. Powertrain Verification Test
NO: Go To 3

3. SCI CIRCUITS SHORTED TO VOLTAGE




Turn the ignition on.
Measure the voltage of the (D21) SCI Transmit (PCM) circuit.
Measure the voltage of the (D20) SCI Receive (PCM) 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. Powertrain Verification Test
NO: Go To 4

4. (D21) SCI TRANSMIT (PCM) CIRCUIT OPEN




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

Q: Is the resistance below 5.0 ohms?

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

5. (D20) SCI RECEIVE (PCM) CIRCUIT OPEN




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

Q: Is the resistance below 5.0 ohms?

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

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




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

Q: Is the resistance below 5.0 ohms?

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