S10/T10 P/U 4WD V6-4.3L VIN X (1996)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
VCM - MIL ON/DTC P1441 Set EVAP System Fault
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 00-06-04-039
Date: September, 2000
Subject:
SES Light Illuminated, DTC P1441 - (Reprogram VCM)
Models:
1996 Chevrolet and GMC S/T Models
1996 Oldsmobile Bravada
With Enhanced Evap and 4.3L V6 Engine (VINs W, X - RPOs L35, LF6)
Condition
Some customers may comment on an illuminated SES light. Further investigation may reveal a DTC P1441. The technician may be unable to determine
the root cause of the DTC. This DTC indicates an EVAP system purge during a commanded non-purge event. A Tech II snapshot during this diagnostic,
or a "system seal" test commanded through the Tech II, will show NO, or minimal, increase in tank vacuum. This code should not set until a minimum
12" H20 vacuum is seen in the tank for 2 seconds when this diagnostic is running (as indicated by the tank pressure sensor).
Cause
A P1441 may set if the VCM detects a change in the fuel control algorithm due to an increase in fuel vapors (rich condition - short-term block learn
values decrease) during the time the diagnostic is running. This may occur due to high RVP fuels, or any event, which may cause a temporary rich
condition. A calibration change was made for 1998 and newer vehicles to address this concern.
Correction
Follow Strategy-Based diagnostics to determine if the DTC code is intermittent and no root cause can be assigned. Reprogram the VCM calibration with
the appropriate calibration from the charts as shown.
Parts Information
For U.S. Applications Use:
For Canadian Applications Use:
The following Canadian AWD application was Not affected by the ABS reflash Special Policy # 99046. Use the listed P/N to install the P1441 "fix".
This calibration can be found on TIS 2000 disk 12 shipped to dealers on 6/21/00.
