SES Light Illuminated, DTC P1441 (Reprogram VCM)

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).

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.

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 below.

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.

The following calibration P/N's to address the ABS Special Policy #99046 also includes the changes to address the DTC P1441 concern.

The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations were available from Techline starting October, 1999 on the TIS 2000 disk 21 and CD-ROM disk 20/21, except for the AWD Canadian application (P/N 09338668) as noted above.

For vehicles repaired under warranty, use: