Hello,

Hoping someone could help me out with the ODB codes I have been getting on my 2004 Blazer. I just pulled the codes and they were:

p0128 - Coolant temp below thermostat regulating temp
p0442 - Evap Emissions control system Leak

These 2 codes have come up in the past and I thought it was taken care of. The dealer said the p0128 was a bad thermostat that was replaced and the p0442 was because my gas cap was coming loose (also replaced).

The code came on as soon as I started my truck this am and was not on before that since the repairs. I read the codes and the p0442 was actually in the reader twice. I really cannot figure what else to check on the vehicle that would cause it to keep throwing the codes. Any ideas??

The only other thing is that I have an exhaust leak on the right manifold at the flange...needs to be repaired. Could this be the cause of my p0442?

Please help....running out of ideas.

Thanks!!

 

this should help

Posted OBDII Trouble Code Diagnosis - Blazer Forum - Chevy Blazer Forums

 

I had the P0128 code. I scanned it at autozone for free and couldn't find anything wrong other than the code, so I bought a scanner with real time monitoring and found the engine's max temp after about 15 miles was 138. The code sets if the engine temp doesn't get up to proper operating temp in a certain amount of time. I put a new thermostat in and problem solved.

I paid $80 for a scanner on sale, and later I found this. It will do everything a scanner will do and more. If I'd have known about it then I would have gotten it instead of a scanner. I'm going to buy one next payday.

UltraGauge Automotive Information Center and OBDII Scan Tool