Powertrain Control Module (PCM) - 66RFE

P0884-POWER UP AT SPEED

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

If a vehicle loses power to the Transmission Control System, the solenoids (L/R, 2C, OD, UD, 4C) will go to their respective power off state. Some solenoids are normally vented and some are normally applied in their power off state. The transmission is designed to be in 4th gear with all of the solenoids in this state. However, if power is restored the Transmission Control System will power-up and normal operation is restored.

This code identifies that power to the Transmission Control System was restored when the gear selector is in a "Drive" position while the vehicle is moving at speeds above 32 Km/h (20 mph). This DTC does not indicate a problem with the transmission or Transmission Control System, instead, it suggests intermittent problems in the fused ignition switch output, fused B(+) or ground circuits to the PCM. Alternately, if a rolling restart maneuver is performed, the DTC can set. Therefore it is critical that this DTC be investigated if the vehicle is experiencing intermittent 4th gear operation and a subsequent return to normal operation.

- When Monitored:
When Powertrain Control Module (PCM) initially powers up.

- Set Condition:
This DTC will set if the PCM powers up and senses the vehicle in a valid forward gear with no PRNDL DTCs and an output speed above 800 rpm, approximately 32 Km/h or 20 mph.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
CHECK THE POWER AND GROUND CIRCUITS
1. This DTC is set when the transmission portion of the PCM is initialized while the vehicle is moving down the road in a valid forward gear.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
3. Check all of the Fused B(+), Fused Ignition Switch Output and ground circuits to the PCM for an intermittent open or short to ground.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC set.

Repair

- Check all power and ground circuits to the PCM and repair as necessary.
- Perform the 66RFE TRANSMISSION VERIFICATION TEST. 66RFE Transmission Verification Test