2004 trailblazer ls 4x4
car was running great then all of out of the blue was baily running stop at oreillys pulled 22 codes out all electrical po300 po128 u13101 b2725 bo790 bo785 bo780bo775 bo770 co 550 co379 co374 co359 co327 co321 co 306 co 305 co 300 co040 co035 v 1064 v1255
With this many code,s showing,there is and issue with the ECM.
The two codes to be concerned with are the P0300 (random/multi-cylinder misfire) and the P0128 (coolant temp below thermostat temp). If your Trailblazer has over 100,000 miles on it you're overdue for a tune up. That could be the reason for the P0300 code. The spark plugs and spark plug wires are worn out. Replace the thermostat with a 195°F one. Sounds like the thermostat is stuck open (P0128). On a computer controlled engine the coolant must reach operating temp (195°F) within a certain time after a cold start or the P0128 code will be triggered. HTH. -Jim
Hello, Clear the codes, and see which one (s) return, but Jim is Spot-On... ECM looks for fast increase in coolant temp to norm, and a few °'s difference makes all the difference in the world to the ECM... Good Luck-- AskTrannyMan
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