Tech - A/C Comp Failure During Aggressive Eng Accel (Reprogram PCM)
| Subject: | A/C Compressor Failure During Aggressive Engine Accelerations (Reprogram PCM) |
| Models: | 1998 Chevrolet Camaro |
| 1998 Pontiac Firebird |
| with 5.7 L V8 Engine (VIN G -- RPO LS1) |
Condition
Some customers may comment on an A/C compressor failure during aggressive engine accelerations, due to compressor over-speed.
Cause
The engine calibration is designed for A/C compressor shut-off at high engine speeds to prevent over-speeding the A/C compressor. In the 1998 model year, timer delays in the engine calibration can result in delayed A/C compressor shut-off during aggressive engine accelerations, resulting in A/C compressor over-speed and possible A/C compressor failure.
Correction
When the compressor is replaced on 1998 vehicles with the LS1 engine, reprogram the Powertrain Control Module (PCM) using the new calibrations found on CD #8 for 1999. This new engine calibration, with reduced timer delays, will provide additional protection against over-speeding of the A/C compressor.
Important: Do not attempt to order the calibration from GMSPO. The calibration is programmed into the vehicle's PCM via a Techline tool.
Use a Techline terminal or scan tool to program the Powertrain Control Module with the calibration appropriate for the vehicle and perform the learn procedure.
To ensure the Powertrain Control Module programming/RPO configuration, confirm that the following conditions exist in order to prepare for PCM programming:
| • | The battery is fully charged. |
| • | The ignition switch is in the "RUN" position. |
| • | The Data Link Connector (DLC) is accessible. |
| • | Refer to the latest Techline terminal and equipment user's instructions. |
| • | Clear the Diagnostic Trouble Codes (DTC's) after the programming is complete. |
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
J6355 | Prom, Reprogramming - On Car | 0.4 hr |
