P0653 Error Code only when jeeps gets to operating temp

C

CDD

New member
Hey guys

Ive been frustrated the last week or so

My Jeep has started to give me a P0653 error code only when the jeeps switches over from closed loop fuel to open loop
giving me a ETC light blinking and ETC light on and engine running as if misfire


Ive tested the harness for short to ground or battery positive and everything checks out

My C1 PCM 5volt does how ever read at 5.2 volts?

Is this normal?
Is this a Faulty PCM?
Any advice will be greatly appreciated
 
CDD said:
Hey guys

Ive been frustrated the last week or so

My Jeep has started to give me a P0653 error code only when the jeeps switches over from closed loop fuel to open loop
giving me a ETC light blinking and ETC light on and engine running as if misfire


Ive tested the harness for short to ground or battery positive and everything checks out

My C1 PCM 5volt does how ever read at 5.2 volts?

Is this normal?
Is this a Faulty PCM?
Any advice will be greatly appreciated
Click to expand...

Before jumping to conclusion that it’s a bad pcm, cause that will be stupid expensive to replace, I would check all the connectors on the motor, check all fuses, and check all grounds on the firewall and frame. Clean up the grounds while in the process. Once done I would clear the code and see if it comes right back.
 
cozdude said:
Before jumping to conclusion that it’s a bad pcm, cause that will be stupid expensive to replace, I would check all the connectors on the motor, check all fuses, and check all grounds on the firewall and frame. Clean up the grounds while in the process. Once done I would clear the code and see if it comes right back.
Click to expand...

Ive checked all the connectors.
All the Pin outs on the PCM
Ive replaced the Throttle Body, The Map Sensor, The Cam Sensor, The Crank Sensor, The Temp Sensor
Ive also replaced the engine control harness as well

My biggest concern is that the jeep runs like a dream when cold and no fault codes. But as soon as the PCM switches over to Open Loop Fueling the ETC light and Fault code pop up
 
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