Intermittent SES Light And DTC P0128 - keywords 3.5L cel cooling HVACLZE LZ4 MIL overheat system thermostat
| Subject: | Intermittent SES Light and DTC P0128 |
| Models: | 2006 Chevrolet Impala, Monte Carlo |
| Equipped with 3.5L (LZE/LZ4) VIN Code K or N engine |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Some owners may comment that the Service Engine Soon light is illuminating intermittently. Upon inspection you may find DTC P0128
Recommendation/Instructions:
Verify that the cooling system is filled to the proper level and using a Tech 2, verify that the thermostat is opening at the proper temperature. If everything is functioning properly advise the vehicle owner that a new calibration for the PCM will be available soon.
In the meantime to avoid the SES light from illuminating advise the customer NOT to operate the HVAC blower speed on high at engine startup. Operating the blower at lower speeds as the engine begins to warm up will reduce the likelihood of the SES light illuminating and will allow for quicker engine and interior warm-ups. Inform them that this document will be updated when additional information is known on the availability of the calibration and that you will contact them at that time.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
