No Response From Powertrain Control Module (SCI Only)

Possible Causes:

• SCI Transmit Circuit Shorted To Ground
• Check PCM Powers And Grounds
• Controller Anti-Lock Brake
• 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. Check Powertrain Control Module (PCM) power and ground circuits. See CHECKING POWERTRAIN CONTROL MODULE POWER & GROUND CIRCUITS  . If problem is not found, go to next step. If any problem is found, repair as necessary and recheck.
2. If vehicle is equipped with anti-lock brakes, go to next step. If vehicle is not equipped with anti-lock brakes, go to step  5 .
3. Turn ignition off. Disconnect PCM connector C3. See Figure . Remove scan tool from Data Link Connector (DLC). Check resistance between PCM connector C3 terminal C27 (Pink wire) and ground. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step  6 .
4. Turn ignition off. Disconnect 25-pin Controller Anti-Lock Brake (CAB) connector. See Figure . Check resistance between CAB harness connector terminal No. 20 (Pink wire) and ground. If resistance is less than 5 ohms, repair short to ground on Pink wire. If resistance is 5 ohms or more, replace CAB. See CONTROLLER ANTI-LOCK BRAKE  under REMOVAL & INSTALLATION.
5. Turn ignition off. Disconnect PCM connector C3. See Figure . Remove scan tool from Data Link Connector (DLC). Check resistance between PCM connector C3 terminal C27 (Pink wire) and ground. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Pink wire.
6. Check resistance between PCM connector C3 terminal C29 (Light Green wire) and ground. See Figure . If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Light Green wire.
7. Check resistance of Light Green wire between PCM connector C3 terminal C29 and DLC terminal No. 6. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Light Green wire.
8. Check resistance of Pink wire between PCM connector C3 terminal C27 and DLC terminal No. 7. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Pink wire.
9. If no other problem is found, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION.