What could cause false 02 sensor codes?

Tiny
MISSY2578
  • 1999 MERCEDES BENZ ML320
  • 12,900 MILES

I've replaced all 4 02 sensors and I'm still getting the codes P0135, P01350 and P0155. It has a brand new catalytic converter as well. I'm stuck.

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Sunday, July 15th, 2012 AT 5:12 PM

5 Replies

Tiny
ASEMASTER6371
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Why did you replace the sensors? A code never identifies a bad part, just a failed system.
Did anyone do a real diag to confirm for you?

I would start from scratch. How did it run? Were there any symtoms? What kind of sensors or brand did you use?

Roy

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Sunday, July 15th, 2012 AT 5:21 PM
Tiny
MISSY2578
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Last year I got a reading the 02 sensor went bad. I changed it. Shortly after the truck started not accelerating. I took it in and the catalytic converter was shot. I replaced it. A day later the codes popped up again for the 02 sensor(s). I took it in to have my tires changed and while it was up in the air, I asked the guy if he could scan my computer again and take a look where the 02 sensor was. He showed me. Whoever put the catalytic converter on at the other shop, melted the harness and 02 sensor. I figured, easy fix. I bought another one. I reset the light and drove about an hour until it came back on, again. Same codes. So, I took it to the first shop whom did the melting of the sensor and wiring harness it plugs into. They said they could not find the harness to purchase so they would have to splice the harness. (Female end) They reset the light and again, an hour later the light came back on. I scanned it and it's the same codes. Something else is triggering it and I'm not sure at what else to look at or test.

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Sunday, July 15th, 2012 AT 5:49 PM
Tiny
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You need to take it back to the first guy who did the damage and have him repair his problem. It should not be your responsibility.

It is a harness issue. No easy fix. It has to be investigated to see how much damage has been done

Roy

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Sunday, July 15th, 2012 AT 5:55 PM
Tiny
MISSY2578
  • MEMBER

I'm not great with vehicles. I can do the basic stuff. One thing though, the codes I'm getting now are for 2 separate sensors. One is a bank one and the other is a bank 2 both being sensor 1. Can that 1 harness give out codes for 2 sensors?

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Sunday, July 15th, 2012 AT 6:15 PM
Tiny
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Sure. Before you address the other codes, the first issue has to be resolved.

Roy

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Sunday, July 15th, 2012 AT 6:27 PM

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