Engine Controls - DTC P0031, P0621, P1637 Update
BULLETIN NO.: 01-T-56ISSUE DATE: November, 2001
CATEGORY TYPE: Engine - 19
CATEGORY: Emission Controls
CORPORATION NO.: 01-06-04-051
SUBJECT:
Service Manual Update for All 2002 L-Series (L81) Engine Service Manuals Regarding DTC P0031, P0621, and P1637 Flowcharts
MODELS AFFECTED:
All 2002 L-Series vehicles equipped with V-6 (L81) engines
PURPOSE:
The purpose of this bulletin is to update all 2002 L-Series (L81) Engine Service Manuals at your location.
Please obtain all 2002 L-Series (L81) Engine Service Manuals and make the necessary updates as indicated below.
1. On page 385 (DTC P0621 Flowchart) and page 431 (DTC P1637 Flowchart), write in the following bulleted step after "Raise vehicle" and before "Using DVOM, measure voltage on circuit 225 at the generator ring terminal."
^ Disconnect generator L-terminal (ring terminal)
2. On page 121 (DTC P0031 Flowchart), write in the following bulleted steps after "Check ENGINE CNTL 3 fuse. Replace and retest if open. If fuse continues to open, check for a short to ground on circuit(s) 2740."
^ Disconnect H025 bank 1 sensor 1. Using DVOM, measure voltage on circuit 751.
DISCLAIMER