No Response From PCM (SCI Only)

Possible Causes:

• Check PCM Powers And Grounds
• SCI Transmit Circuit Shorted To Voltage
• Transmission Control Module
• SCI Receive Circuit Shorted To Voltage
• SCI Circuits Shorted Together
• SCI Transmit Circuit Shorted To Ground
• SCI Receive Circuit Shorted To Ground
• SCI Receive Circuit Open
• SCI Transmit Circuit Open
• Powertrain Control Module

Testing

1. With the DRBIII(R) in the generic scan tool mode, attempt to communicate with the PCM. If the DRBIII(R) can communicate with the PCM in the generic scan tool mode, it may not be necessary to perform this step. Did the vehicle pass this test? If yes, go to next step. If no, repair as necessary. Perform POWERTRAIN VERIFICATION TEST VER-1  .
2. Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the DRBIII(R) from the DLC. Measure the resistance between ground and the SCI Transmit circuit. Is the resistance below 5.0 ohms? If yes, go to next step. If no, go to step.  4 .
NOTE: If vehicle is not equipped with a TCM, answer yes to the question.
3. Turn the ignition off. Disconnect the TCM harness connector (if equipped). Measure the resistance between ground and the SCI Transmit circuit. Is the resistance below 5.0 ohm? If yes, repair the SCI Transmit circuit for a short to ground. Perform POWERTRAIN VERIFICATION TEST VER-1  . If no, replace the Transmission Control Module. See TRANSMISSION CONTROL MODULE (TCM)  . Perform POWERTRAIN VERIFICATION TEST VER-1  .
4. Turn the ignition on. Disconnect the DRBIII(R) from the DLC. Disconnect the PCM harness connectors. Disconnect the TCM harness connector (if equipped). Turn the ignition on. Measure the voltage of the SCI Transmit circuit at the DLC connector (cavity 7). Is the voltage above 1.0 volt? If yes, repair the SCI Transmit circuit for a short to voltage. Perform POWERTRAIN VERIFICATION TEST VER-1  If no, go to next step.
5. Turn the ignition off. Disconnect the DRBIII(R) from the DLC. Disconnect the PCM harness connectors. Turn the ignition on. Measure the voltage of the SCI Receive circuit at the DLC connector (cavity 6). Is the voltage above 1.0 volt? If yes, repair the SCI Receive circuit for a short to voltage. Perform POWERTRAIN VERIFICATION TEST VER-1  . If no, go to next step.
6. Turn the ignition off. Disconnect the DRBIII(R) from the DLC. Disconnect the PCM harness connectors. Measure the resistance between the SCI Transmit circuit and the SCI Receive circuit at the PCM connector. Is the resistance below 5.0 ohms? If yes, repair the short between the SCI Transmit and the SCI Receive circuits. Perform POWERTRAIN VERIFICATION TEST VER-1  . If no, go to next step.
7. Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the DRBIII(R) from the DLC. Measure the resistance between ground and the SCI Receive circuit. Is the resistance below 5.0 ohms? If yes, repair the SCI Receive circuit for a short to ground. Perform POWERTRAIN VERIFICATION TEST VER-1  . If no, go to next step.
8. Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the DRBIII(R) from the DLC. Measure the resistance of the SCI Receive circuit between the PCM connector and the DLC. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the SCI Receive circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-1  .
9. Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the DRBIII(R) from the DLC. Measure the resistance of the SCI Transmit circuit between the PCM connector and the DLC. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the SCI Transmit circuit for an open. Perform POWERTRAIN VERIFICATION TEST VER-1  .
10. If there are no possible causes remaining, replace and program the Powertrain Control Module. See POWERTRAIN CONTROL MODULE (PCM)  . Perform POWERTRAIN VERIFICATION TEST VER-1  .