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2003 S55 AMG
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348 Posts
Discussion Starter #1
Hey Guys,
My rear o2 sensor keeps giving the same error no matter what 02 sensor i try (i have a couple of them laying around, some new non oem and the originals that i took out at 100K miles).
I get P0161 which is heater circuit, and P0170 which is trim Fuel Trim Malfunction.

My air mass sensor is relatively new and the car drives well (I can tell I get good gas mileage, and I've owned it long enough to 'feel' when its not running spot-on"

So I am suspecting wiring problems maybe or maybe a fault in the computer??. Before I go and investigate, does anyone have any experience in a common failure? The 02 connector looks good with clean contacts and mates well, the wires up into the harness near the transmission pan also look in good shape.

anyone got any good trouble shooting tips?

thanks in advance 2000 E430 120K miles, passenger side that has an after market cat installed. I did not have problems for a long time after the after market cat was installed.

Jim
 

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99 E430, 01 E430 Sport, 00 SL500
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3,266 Posts
Put the left sensor to right, right to left to see if the OBD codes follow ... then you'll know.
Don't forget to apply a little bit of anti-seize in the final replacement.
 

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Registered
2003 S55 AMG
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348 Posts
Discussion Starter #3
Thanks I thought about that but wondered if that would just confuse the CPU and create more error codes. I'll go try it now. Cheers.
 
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