Code P0155

Tiny
TIM GOODLIFFE
  • MEMBER
  • 2002 MITSUBISHI MONTERO
  • 3.5L
  • V6
  • 4WD
  • AUTOMATIC
  • 165,000 MILES
After rough idle and I had p0154 and p0172 I cleaned the mass airflow sensor and replaced the 02-sensor bank 2 sensor one (driver side pre-cat), both of those codes disappeared and were replaced by p0155. I will be checking the connections tomorrow for power as well as probably inspecting the lines back to the ECU.
Saturday, October 16th, 2021 AT 7:28 PM

8 Replies

Tiny
TIM GOODLIFFE
  • MEMBER
  • 7 POSTS
Please note that the standing voltage of the sensor (at idle) before replacement was about.04 (bank 1 was.20) and after replacement was.72 (bank 1 was.76) so much closer.
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Saturday, October 16th, 2021 AT 7:47 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi,

Checking the wiring and the connections is a perfect place to start. If that doesn't help, then we need to move to checking the circuit.

Is the engine running normally? The code indicated there could be a short, an open circuit, or even a PCM issue.

If you look below, I attached the diagnostics specific to this code. Let me know if you are comfortable performing the tests.

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.
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Saturday, October 16th, 2021 AT 11:33 PM
Tiny
TIM GOODLIFFE
  • MEMBER
  • 7 POSTS
Realized that I had put this as a Montero and not a Montero sport. I own a 2002 Montero sport.
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Saturday, October 16th, 2021 AT 11:42 PM
Tiny
TIM GOODLIFFE
  • MEMBER
  • 7 POSTS
It runs pretty rough at idle.
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Saturday, October 16th, 2021 AT 11:43 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Hi, Tim.

The Sport has the same procedures listed. That's fine. Have you had a chance to check the wiring? Also, by chance, do you have a live data scan tool? If you do, could you let me know the short-term fuel trims? Also, let me know if you have checked for vacuum leaks, fuel pressure, and basic system checks.

I'll watch for your reply.

Joe
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+1
Sunday, October 17th, 2021 AT 8:22 PM
Tiny
TIM GOODLIFFE
  • MEMBER
  • 7 POSTS
Hi Jacob, I did check for vacuum leaks, it is possible that one of the boosters or a vacuum line has a leak that I did not find, but I looked pretty carefully, I have screenshots of pretty much all the basic system checks, (have not checked fuel pressure yet that seems like a good one).
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Sunday, October 17th, 2021 AT 11:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,055 POSTS
Tim,

If possible, check the fuel pressure. Also, if you follow the link I provided above, it will show how to find leaks that aren't visible.

Let me know what you find.

Joe
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Monday, October 18th, 2021 AT 4:58 PM

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