OT: PO173 code but no CEL
12-17-2005, 02:08 PM
#1
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OT: PO173 code but no CEL
I did not have a check engine light and the check engine light bulb does work.
I was clearing a code on another car and I thought I'll check the Mercedes 1999 ML 320. The code is fuel trim malfunction bank 2. And like I said I have no CEL. I cleared the code without any problem.
What might be going on. The vehicle runs perfectly.
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I was clearing a code on another car and I thought I'll check the Mercedes 1999 ML 320. The code is fuel trim malfunction bank 2. And like I said I have no CEL. I cleared the code without any problem.
What might be going on. The vehicle runs perfectly.
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12-17-2005, 08:11 PM
#2
Instructor
Something to consider
I got the same code on my CL 500 and after checking the code descriptions, I had two options O2 sensor malfunction or the beginning of a MAS failure. Replaced the MAS and cleared codes 4 months ago, and it never returned. Just my .02cents
12-17-2005, 08:22 PM
#3
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How many miles on your vehicle when you replace MAS, I'm at 112K on mine.
I had a CEL a few months ago for a bank 2 after CAT sensor. I reset it and never came back. That code had a different number than what I got this time. I know the computer parameters for the O2 sensors are very narrrow and the vehicle will often run fine even if the O2 sensors are not withing computer parameters. The O2 sensors seem fine this time.
Lots of people have had MAS failure at much lower mileage than mine.
I had a CEL a few months ago for a bank 2 after CAT sensor. I reset it and never came back. That code had a different number than what I got this time. I know the computer parameters for the O2 sensors are very narrrow and the vehicle will often run fine even if the O2 sensors are not withing computer parameters. The O2 sensors seem fine this time.
Lots of people have had MAS failure at much lower mileage than mine.
