Intermittent Malfunction Indicator Lamp (MIL) and PCM DTC P1404 (Recalibrate PCM)

This bulletin is being revised to update the calibration information to the latest available. Please discard Corporate Bulletin Number 01-06-04-018 (Section 06-Engine).

Some customers may comment on the MIL illuminating intermittently with no other driveability concerns noted. Upon investigation, the technician may find a stored PCM Diagnostic Trouble Code (DTC) P1404.

The EGR valve pintle position voltage may not correlate to anticipated PCM calibration values.

Important: Verify that the TECH2® has been updated with software version 21.000 (Released January 23, 2001), or greater before attempting the procedures in this bulletin.

1. Prior to recalibrating the PCM, verify the following diagnostic values with a Tech2® using the following steps:

1.1.	In the Powertrain engine data menu, select F2 EGR Data. Press enter.

1.2.	With key ON, engine OFF, view the EGR Position Sensor Percentage (%).

2. If the actual position is greater than 3.8 percent, and no other EGR codes or symptoms are present, then proceed to Step 4. Otherwise, proceed to Step 3.
3. If the actual EGR pintle percentage observed in Step 1.2 is less than 3.8 percent, or if other EGR codes or symptoms are present, then proceed with the published diagnostics found in SI. When the appropriate repairs are completed, proceed to Step 4.
4. PCM calibrations to correct this issue have been released for service. Reprogram the PCM using TIS 2000 version 1 for 2002, or later.

The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline® starting January 2002, on the TIS 2000 version TIS 01/2002 data update or later.

For vehicles repaired under warranty, use: