P0884-POWER UP AT SPEED





For a complete wiring diagram Refer to Section 8W.

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 3rd gear with all of the solenoids in this state. However, if power is restored, the Transmission Control System will power-up and normal operation will be restored.

This code identifies that power to the Transmission Control System was restored when the gear selector was in a "Drive" position while the vehicle was 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 TCM. Alternately, if a person performs a rolling restart maneuver, the DTC can be set. Therefore it is critical that this DTC be investigated if the vehicle is experiencing intermittent 3rd gear operation and a subsequent return to normal operation.



Possible Causes
POWER UP AT SPEED


Always perform the 45RFE/545RFE Pre-Diagnostic Troubleshooting Procedure before proceeding. (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 45RFE/545RFE - STANDARD PROCEDURE)



Diagnostic Test

1. CHECK THE POWER AND GROUND CIRCUITS

This DTC is set when the Transmission portion of the Powertrain Control Module is initialized while the vehicle is moving down the road in a valid forward gear.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
Check all of the Fused B(+), Fused Ignition Switch Output, and ground circuits to the PCM for an intermittent open or short to ground.
With the scan tool, check the DTC EVENT DATA to help identify the conditions in which the DTC was set.

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Repair