Powertrain Control Module (PCM)
WARNING: This page is about a different car, the 2004 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
The PCM is the only module on the SCP communication network. If one of the bus wires becomes shorted to ground or voltage, or if some but not all termination resistors are lost, communications can continue. Check circuits 915 (PK/LB) and 914 (TN/OG) between the PCM C175 and the DLC C251. Total resistance values must not be more than 5 ohms. If the resistance is more than 5 ohms there is an open circuit in the SCP network, damage to the DLC C251, damage to the PCM C175, or a problem in the in-line connector.