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Malfunction Indicator Light (MIL) on with DTC P0446 Code Set (Reprogram PCM)

Subject:Malfunction Indicator Lamp (MIL) On With DTC P0446 Code Set (Reprogram PCM)

Models:1998-2000 Chevrolet and GMC C/K Models
with 7.4 L Engine (VIN J -- RPO L29) and California Emissions (NB6)



Condition

Some customers may comment on a Malfunction Indicator Lamp (MIL) that is illuminated. Further investigation will find a DTC P0446 code has been set.

Cause

The code is more likely to occur with less than 1/2 tank of fuel. The VCM monitors the performance of the EVAP system by applying a predetermined level of vacuum to the EVAP system. The VCM then monitors the vacuum decay rate. The VCM sets this DTC if the vacuum decay rate is greater than a predetermined value. The decay rate at idle is higher than the monitoring portion of the current calibration range will allow.

Correction

Once the vent solenoid is verified to be operational, reprogram the vehicle with a new calibration.

Parts Information

The calibrations listed are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting on the TIS 2000 CD 13 shipped to dealers 7/6/00.

Model Year

Original Production Calibration Part Number

New Service Calibration Part Number

1998

16250416

9388662

1998

16250419

9388663

1999

9351030

9388664

1999

9351033

9388665

2000

16259196

9388666

2000

16259199

9388667

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation

Description

Labor Time

J6355

Prom - Reprogramming, On Car

Use Published Labor Time