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2020 Ford Mustang GT P0036, P0138, P0141 02 sensor help

  • Thread starter Thread starter AmkoA
  • Start date Start date Jul 29, 2025
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    o2 sensors
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AmkoA

New Member
Jul 29, 2025
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NY
Jul 29, 2025
#1
  • Jul 29, 2025
  • #1
Hello,

After installing SW long tube headers with no cats, I went over a bump on the road and a check engine light appeared stating there is a malfunction with the Bank 1 Sensor 2 O2 sensor. Lund tune. Turns out the sensor got pulled/ripped into the driveshaft. Ever since I have been having random misfires at low and high RPM. Changed the O2 sensor with an OEM one and still had the codes. Then the harness ( LR3Z14300C) was also changed which did not resolve the issue. I confirmed with the Ford parts department that this was the correct harness which connects to the O2 sensor. Link of where I bought the harness below. I took it to a local mechanic shop and they had told me based on their evaluation of the harness and electrical system, there is a break/short somewhere. The issue is they are very expensive and cannot give an estimate of what the price will be. They had even told me it could be over $2000 to find and fix the break. Therefore, I want to see if there is something I can do. I have decent mechanical skill but not great is electronic diagnostics. I took a crack at it today and if I did it correctly, the volts going to the sensor on the harness side around 0.45. I was also getting fluctuations of OHMs for the 2 heater wires from 0-50 (granted again I did it correctly). I don't understand how there could still be a break when the sensor AND harness was changed. My only thought could be the ECM being damaged because of the pull. Fuses looked fine. I had one on me blow in the past and it was replaced with resolution of those codes. Any help at this point would be appreciated because I am lost.
 

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skkrtis

New Member
Apr 6, 2025
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Corpus christi tx
Aug 5, 2025
#2
  • Aug 5, 2025
  • #2
Wouldn't having no cats trigger a check engine light from sensor 2's? Sensor 2's check and monitor catalytic converter. If yours are removed, hence the check engine light. Your misfire could be elsewhere
 
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