p0138

Hi. New to the forum. Purchase used 2001 Wrangler SE 2,5L 5 speed. 106K miles. CEL was on but I guess I overlooked since the body and frame were solid. Issue: Very rough idle when cold. Gets a little better when warm. Auto zone CEL codes are P0303, P0132, P0304, P0138, P0455, P0303...

I bought my Jeep a few months ago and shortly after I got home with it some check engine lights came on. I haven't had much time to work on it yet, but I am trying to diagnose the main problem first. The codes it is throwing are P0031 (Oxygen (A/F) Sensor Heater Control Circuit Low Bank 1...

P0037 Powertraine H028 Heater control circuit Low (bank 1 sensor 2) and: P0138 Powertrain O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) The rig runs fine. I replaced the O2 sensor down on the exhaust pipe. Is there another hidden? I do not have a catalytic converter and as it is a...

Ok guys, I’ve got one for you. I’ve had my 97 TJ for a couple of years now. Recently the MIL came on and showed a P0138 and a P0141 for downstream o2 sensor heater circuit. I said ok, I bought an o2 sensor online (not Bosch) and installed it. Code went away for about a day and then came back...