Repeat Service Engine Soon (SES) Light at Low Mileage and Diagnostic Trouble Code (DTC) P0420 (Reprogram ECM)
| Subject: | Repeat Service Engine Soon (SES) Light at Low Mileage and Diagnostic Trouble Code (DTC) P0420 (Reprogram ECM) |
| Models: | 2005 Chevrolet Cobalt |
| 2005 Pontiac Pursuit (Canada Only) |
| with Ecotec 2.2L 4-Cylinder Engine (VIN F - RPO L61) |
| Built Prior to VIN Breakpoint 57615549 and April 18, 2005 with RPO M86 and 16 Inch Tires |
This bulletin is being revised to update the warranty information. Please discard Corporate Bulletin Number 05-06-04-030A (Section 06 - Engine/Propulsion System).
Condition
Some customers may comment on a Service Engine Soon (SES) light with low mileage (typically under 322 km (200 mi)). Some vehicles may have previously been serviced for this same condition.
Technicians may also find a DTC P0420 which may have led to previous catalytic converter replacements.
Cause
The ECM initiates a diagnostic test that monitors catalytic converter efficiency. If this test fails, a DTC P0420 will set. Typically, on new vehicles, an internal ECM delay timer prevents this test from running for a short period of time so the catalytic converter can break in and increase efficiency. This timer may become disabled if the battery of a new vehicle has been discharged or disconnected, or if a power interruption occurs during vehicle manufacturing. As a result, this test may run before the catalytic converter has had time to break in and increase efficiency, resulting in a DTC P0420.
Correction
Reflash the ECM with the latest ECM calibrations if the above concern is encountered.
Important: In order to ensure that the performance of the catalyst has not been affected by the fault that set this DTC, operate the vehicle within the Conditions for Running and the Conditions for Setting DTC P0420 and verify that DTC P0420 runs and passes.
An updated ECM calibration is now available to address this concern. The title of this calibration is "New Calibration for Improved Fuel Gauge Accuracy. Also Contains Diagnostic Enhancements for DTCs P0420 and P0461". This calibration, or any that follow, is designed to address this concern. This calibration was available to dealerships on 3/7/2005 as part of TIS2000 Incremental Satellite Update 3.0 (NAO Version 04.4). As always, make sure your TECH 2® is updated with the latest software version.
Warranty Information
For vehicles repaired under the 8-year/80,000-mile (130,000 km emission controller warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
J6353 | Module, Powertrain Control - Engine Reprogramming | Use Published Labor Operation Time |
