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From: Phoenix
Your coolant is too low a temp for closed loop control. The PCM needs to see at least 170 degrees coolant temp before it allows the O2 sensor inputs to drive the A/F mixture which then, by definition, means you are in closed loop control. Instead, it operates off of a predefined A/F and spark curve table, with some correction factors possible from other sensor inputs such as intake air charge temp.
I would first verify that in fact the coolant is a low temp. When car is cold, remove radiator cap and insert a thermometer. Take one of those glass faced turkey temp testors out of you wife's kitchen if you don't have one in the garage. Stick it right into the radiator. Start it up and watch. If you are getting over 170 degree F after the therostat opens, then the temp sensor is bad. If it doesn't warm up, it's probably your thermostat opening too soon or stuck open, not allowing the engine to get hot.
Other question is the CEL still comming on? Did you clear the code and have it come back. I wonder if this is a recurring issue or just a once off that might have happened on a cold morning and you just now checked and saw an old code.
I would first verify that in fact the coolant is a low temp. When car is cold, remove radiator cap and insert a thermometer. Take one of those glass faced turkey temp testors out of you wife's kitchen if you don't have one in the garage. Stick it right into the radiator. Start it up and watch. If you are getting over 170 degree F after the therostat opens, then the temp sensor is bad. If it doesn't warm up, it's probably your thermostat opening too soon or stuck open, not allowing the engine to get hot.
Other question is the CEL still comming on? Did you clear the code and have it come back. I wonder if this is a recurring issue or just a once off that might have happened on a cold morning and you just now checked and saw an old code.
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