Closed loop problem.
Thread Starter
Race Director
Joined: Jun 2004
Posts: 13,939
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From: WI
Closed loop problem.
When I run in diagnostic mode (car warmed up) my PCM shows open loop fast flashing of SES, and then goes into closed loop slow flashing of SES but only stays that way for around 30 seconds. Then flashes fast open loop and will stay that way. What could be wrong? I have tried keeping the car at a high RPM but that had no effect. I have tried a spare O2 sensor. My car is slightly rich and runs fine otherwise. I'd like to be in closed loop for better MPG!
I am thinking, bad ground, bad wiring to o2 sensor, or bad PCM. To test my wiring back to the PCM from the 02 pigtail what would I look for on my mulitmeter to know that I'm talking to the PCM? What'd the best method to test my grounds?
Thanks for the help!
I am thinking, bad ground, bad wiring to o2 sensor, or bad PCM. To test my wiring back to the PCM from the 02 pigtail what would I look for on my mulitmeter to know that I'm talking to the PCM? What'd the best method to test my grounds?
Thanks for the help!
