2003 Chevrolet Blazer Q&A

2003 Chevrolet Blazer Question: My car failed emission test engine light has been on awhile

Results of emission koeo..........pass koer..........fail communication pass tamper.......pass mil command..fail Troublecodes po128 coolant thermostat temp below po449 evaporative vent valve/solenoid cir po455 leak lg detected -
Answer 1
128 is most likely a thermostat failing. the evap codes need a shop with a scan tool, smoke machine and voltmeter to determine the failure. Roy -
Comment 1
Thanks will that determine po455 leak also. Is this going to be expensive? -
Comment 2
the diag is about an hour labor with the correct tools. price?? do not know what has failed. it will not be cheap, thats about all i can say. Roy -