DRB "No Response"Message

A "No Response" message is displayed whenever the Diagnostic Readout Box (DRB) is unable to communicate with the Powertrain Control Module (PCM). For any communication with the PCM, the ignition key must be in either the RUN or CRANK position. If the DRB is unable to communicate with the ignition key in the proper position, perform the following steps:

1. Disconnect the PCM and ensure that PCM cavities 25 and 45 are not damaged, pushed out, or miswired.
2. Disconnect the DRB from the data link connector.
3. Using an ohmmeter:

- Ensure the SCI transmit and SCI receive circuits (PCM cavities 24 and 45 respectively) are not shorted to ground.
- Ensure the SCI transmit circuit is complete between PCM cavity 25 and data link connector cavity 3.
- Ensure the SCI receive circuit is complete between PCM cavity 45 and data link connector cavity 5.

If both the SCI transmit and SCI receive circuits are found to be good through the steps above, and the DRB still displays a "No Response" message, then replace the PCM.