# One cause and solution for P0036, P0138, P0140 and P0041 codes.



## Blasirl (Mar 31, 2015)

I had finally gotten the car to running in excellent fashion. Things were looking good. I then ran into / over some big chunk of metal lying in the street. I heard a loud bang and a screech and it was over. It was too dark to see much under the car and nothing was hanging or dragging, so I went home. The next morning I had a check engine light. It was showing the three codes and since I had to go to work the next day, there was enough time for a fourth code to show up as well.

P0036, P0138, P0140 and P0041. (Listed below are the basic causes with the common thread in italics.)

I was able to put the Bomb up on stands the next day and took some pictures of the undercarriage. It seemed that the two sensors were OK, the flex coupling for the down-pipe to mid-pipe was slightly damaged and that the exhaust cross-member took the brunt of the damage. I tested the continuity from the exhaust to the block and it seemed OK. I was stumped and needed to get the car back to normal sooner rather than later as I have to renew my plates this month, so I enlisted my trusty mechanic to figure it out for me.

He found the issue right away when he put it up on the lift. The connector on the rear O2 sensor was unplugged. He thought it would be an easy fix. He did have a tough time connecting it though as the entire exhaust was moved backwards due to the impact. Once he did get it connected, he cleared the codes and started it up. The codes came right back. He went back under and looked a bit closer. Both of us had missed an important clue. Look closer at the picture of the rear sensor. It is bent.

Apparently the impact forced the exhaust up and into the body as well as pinching the connector between the trans and steering. Needless to say, once a new sensor was installed (GM 5557-2216 / ACD 213-4698), he had to beat the cross-member back towards the front and also adjust the hanger brackets as well in order to get enough slack for the wiring to be able to move freely with suspension movement. In the future, I'll pull a replacement bracket from an LKQ vehicle, so I do not have any issues installing my Magnaflow exhaust.

Now on to have my emissions tested before I do something else to her. 

Potential causes of a *P0036* trouble code may include:
Open circuit inside oxygen sensor or _open power or ground wires_ to oxygen sensor
Exhaust system ground strap may have become corroded or broken PCM/ECM or oxygen sensor heater circuit wiring has failed

Read more at: https://www.obd-codes.com/p0036

A code *P0138* may mean that one or more of the following has happened:
Faulty O2 sensor
_Short to battery voltage_ in O2 sensor signal circuit
High fuel pressure (not as likely)

Read more at: https://www.obd-codes.com/p0138

The causes for a *P0140* code are fairly few. They could be any of the following:
_Shorted heater circuit_ in O2 sensor. (Usually requires replacement of heater circuit fuse in fuse block also)
_Shorted signal circuit_ in O2 sensor
Melting of harness connector or wiring due to contact with exhaust system
Water intrusion in harness connector or PCM connector Bad PCM

Read more at: https://www.obd-codes.com/p0140

A code *P0141* may mean that one or more of the following has happened:
_Open or short to ground_ in the wiring harness
O2 heater circuit wiring high resistance
O2 heater element resistance is high Internal short or open in the heater element

Note: Typically a failed catalytic converter does not cause this code. You're more likely to see a P0420 code for a failed converter.

Read more at: https://www.obd-codes.com/p0141


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## WillL84 (Aug 5, 2019)

That'll do it! One hell of a bump there lol


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## Blasirl (Mar 31, 2015)

Runs like a champ now. I went to get it emission tested yesterday, but their software package was on the fritz. I have to work all this weekend, so maybe Monday.


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