05 LJ CEL (long read)

[MRChiefE7]

07/07/2024
It all started with codes P0031, P0037, P0051 & P0057, cleared the codes.

07/08/2024
This time it has only (1) code P0151, cleared the codes

07/09/2024
This time it has the same code P0151 again. At this point I placed a call to you at wrangler fix. Based on my discussion with them we ordered a new PCM. The mileage at this time is 84020.

07/13/2024
I received the new PCM and installed it with no problems.

08/2024
I started getting a CEL again with a code P0431 (warm up catalytic converter bank 2 – efficiency below threshold). I unplugged the new PCM to clear the code per Wrangler Fix instructions but code returns.

09/2024
My grandson needed transportation and asked if he can use the jeep after his truck burned up.

10/2024
After getting the jeep back I checked for codes and I now have (2) new additional codes. They are codes P0157 (band 2, sensor 2 – oxygen sensor circuit low voltage), P0158 (bank 2, sensor 2 – 02 sensor circuit high voltage) along with the P0431 (warm up catalytic converter bank 2 – efficiency below threshold).

11/2024
Well I am finally getting around to trying and fixing the CEL problem with my LJ. I have disconnected the (4) plugs at the PCM clearing all codes. I test drove to see what code/s show up now. The mileage is now at 85899. After driving (3) blocks the CEL returned. Checked for codes using my key and noted code P0158 again. After driving 61 miles (85961) to see if any other codes would show up. No additional codes at this time. So on 11/29/2024 I ordered a new (NTK 23158) O2 sensor for the bank 2, sensor 2.
12/07/2024
After installing the new O2 sensor, I unplugged the (4) plugs at the new PCM to clear the existing code again. After driving 26 miles (85987) the CEL came on again. Stopped and checked for code/s finding code P0157 has shown up again. Drove home an additional 13 miles (86000) and checked for codes again. I am now seeing (2) codes P0157 & P0158.

12/08/2024
To see if any changes I install the old PCM. I started the jeep and got the original codes (P0031, P0037, P0051 & P0057) like we had back in July. So it’s a no go with the old PCM.

12/11/2024
I contacted Wrangler Fix to see what they have to say and asked to send the PCM to them for inspection. I shipped the PCM back to them for inspection to insure that the problem(s) were not being caused by the PCM.

12/26/2024
I got the PCM back from Wrangler Fix and installed today and after starting the Jeep all was looking good with no CEL. After driving approx. 10 miles the CEL came on so I pulled into a parking lot to check for codes. I am seeing the P0158 code again using my key to check for codes (86121).

12/27/2024
Checking for vacuum leaks the little line at the manifold was loose so I put a tri wrapped around it. I also noticed that the gas cap seal was damaged. Pleased the gas cap (86121).

12/28/2024
Test drove the jeep and all was good for 30 miles (86151). Stopped to for gas and after restarting the engine the CEL came on again. Same code P0158.

12/31/2024
Removed and cleaned the (2) ground wires on the fire wall and the (1) on the hood. Cleared the PCM and test drove again (86171). Made a stop and after restarting the engine the CEL again (86178). Same code P0158.

I do not what else to do accept to take the jeep to a shop for testing and repair.

2005 Jeep Wrangler TJ Unlimited (LJ)
Engine: 4.0
Transmission: Automatic

 

[97' 4 Popper]

I have nothing to add except I also have a 2005 LJ with the same codes, they go away in winter and come back in summer. I was thinking about getting the Wrangler Fix PCM, which is the usual suggestion. I'm curious what you find out next.

One thing is for sure, I will never buy another 2005 or 2006.

 

[MRChiefE7]

We have had the jeep going 10 years now. Outside standard maintains items there have no problems with the jeep.

 

[Chris]

Perhaps have @Wranglerfix test your PCM for you.

 

[MRChiefE7]

Already did that. Just got it back and installed on 12/26/2024

 

[DuckNut]

Did you change both O2 sensors? Did you use name brand or Autozone special?

Also, a failing catalytic converter can cause these codes - P0158 specifically.

157 and 158 are related so it is reasonable to assume if one triggers it won't be long before the other shows up.

 

[MRChiefE7]

As reported above (12/07/2024) I did install a new (NTK 23158) O2 sensor for bank 2, sensor 2 only based on the p0158 code. I do not hear any exhaust leaks. And yes, the catalytic converter may be the problem also.

 

[MRChiefE7]

I have made an appointment to have the system tested to determine the cause of the CEL code P0158 on the 16th. I will update you on what they find.

 

[MRChiefE7]

I did not make my appointment for testing for the CEL code P0158. I have rescheduled for the 29th and will update you on what they find out.

 

[MRChiefE7]

Well, got the jeep back from the shop this afternoon. I am glad to report that they were able to find/fix the problem. I was a broken wire near the firewall from the 02 bank 2 senser to the PCM. the total cost $348.00 with the testing and fix. The LJ and I am very happy to put this to bed.