2004 Chevy Trailblazer Has Many SES Light Codes

4.2L Straight Six cylinder engine. 2004 Chevy Trailblazer LT 4x4. SES light on. GM Computer codes p0128, p0172, p0410, p0455, p0606. Check engine light came on about 1 week ago.  Cold weather. Took to garage, ran codes and 5 codes came back.

The garage checked out a few of the codes and said that all values and sensors were fine.  Garage did not specify which codes they checked.

Said they only checked out a few of the
codes. SES will not reset, comes right back on with the same codes.  Mechanic feels that it must be the computer and it needs replaced.  I have read that if the computer is bad, the vehicle will run rough.  It runs fine, no indication of anything wrong other than SES light.  Could there be something else causing all these codes, something simple instead of replacing the computer.

Answer: Did the SES light ever come on before that time? I need to know if any of these codes came before any of the other codes.With the light on, some of codes may have been in history, meaning they happened at a different time, and may not all came on the same time. This is important because all these
codes are different systems, but can be related depending on which one come on at the same time together. See if is states anything like that on the receipt or have it cleared and get codes scanned again when light comes back on to see which ones come back together. I would need this info before i can look at ALL these codes.

Reply: As of right now, the SES light has been an ongoing thing.  It is always a different reason why it is on.  Oxygen sensor, other sensors related to emissions system, specifically the secondary air system.  The garage has replaced parts to it, about a year ago. Those parts were the first they checked and they said they are fine.  I don't even remember all codes.  Everything has been running great for about a year.  Haven't had the light on.  Light came on about a week ago and my husband drove it for the entire week with the light on before we put it in for service. The garage did not tell us which codes were in history and which were new.  They just gave us a list of codes.

The next day after the garage looked at it is when we noticed gas smell and from a full tank, saw that it was burning through gas fast.  Which would make sense with the two of the codes, P0455-large leak, P0172-running rich.  Garage said they cleared the codes several times and each time they cleared the SES light came right back on with the same codes.  Basically they said it was probably the computer giving false codes and to call the dealership.  In the meantime, took it to another garage.  Found a loose wire, I believe a ground wire perhaps. Not sure what wire, to what system, but found a loose wire, tightened back where it belonged and cleared the codes. That was yesterday, so far the SES has not come back on.

Can let you know if SES comes back on, driving it today to see if light comes back on. I wonder if it were something that simple like a loose wire that caused it all?  On a side note, I have  a Chevy Impala 03, that had ABS light with service traction soon code c1218 I think anyhow, turned out to be a loose ground wire.  Tightened wire back in its place, light reset, hasn't been back on since, about 3weeks now.

Answer: The P0455 would have nothing to do with running rich, or the P0172 code. P0455 is usually a gas cap problem, or a vent solenoid. P0128 is Coolant temp below thermostat operating threshold. This is usually caused by a faulty thermostat. That may cause the rich code, since engine temperature is not high enough, and engines always burn more gas when cold as compared to being warmed up. P0606 is an internal fault in the PCM. This may be the cause of more than just this codes, or only this code. The ground may have fixed this one. Also, there is a PCM programming update for this year to correct false P0606 code before having it replaced. Warranty for a bad PCM is 8 years, 80,000 miles.

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  • Guest - Rene Travis

    P1680, what are does that mean