GM Service Manual Online
For 1990-2009 cars only

Hard Start, No Start, Caution Light , Corrosion at C305 - keywords communication connector DTC entertainment information inoperative nostart SES

Subject:Hard start, no start, caution light, Corrosion at C305

Models:2005-2006 Buick Terraza
2005-2006 Chevrolet Uplander
2005-2006 Pontiac Montana SV6
2005-2006 Saturn Relay



This PI Supercedes To Remove OnStar From Keywords. Please Discard PIC4072.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Customers may complain of a caution light, or hard/no start condition. Initial analysis may find corrosion at connector C305

Recommendation/Instructions:

If this is the case, remove carpet from the rear and look for evidence of water on the inside of the vehicle, pooling above C305. Origin of leak is most likely at the rear of the left wheel house. Seal the leak, dry the floor pan, and repair the C305 connector.

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.