A/T - 4T80E DTC P0748 Diagnostic Procedure
File In Section: 07 - Transmission/TransaxleBulletin No.: 01-07-30-027
Date: October, 2001
INFORMATION
Subject:
Referencing DTC P0748 Diagnostic Procedure For Harsh Shift and/or Harsh Garage Shift Concerns
Models:
2001 Cadillac DeVille, Eldorado, Seville
2001 Oldsmobile Aurora
with 4T80-E Automatic Transmission (RPO MH1)
In some instances, when diagnosing concerns on harsh shifts while driving and/or harsh garage shifts, a Diagnostic Trouble Code (DTC) P0748 may be set. When a DTC P0748 is set, one of the actions taken is to default line pressure to a high value. As a result, shifts will have a harsher feel. Causes for the DTC P0748 may be in the pressure control (PC) solenoid valve, internal or external wire harnesses, or the powertrain control module (PCM). If DTC P0748 is set, published diagnostics will successfully lead the technician to replace the correct component. It is important to follow the step procedures for DTC P0748 to correctly identify the root cause of the high line pressure and avoid replacing good components.
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