There is no telling on how much the repairs to your truck will cost at this
point. The reason the check engine light is on needs to be diagnosed first.
Once a smog check repair station connects a check engine light scanner to
your GMC they will retrieve trouble codes from the engine control computer
indicating which emission system is having a problem. Based on that they can
give you an estimate of how much, and what repairs need to be done.
posted by SmogTips Support
