Help with Engine Codes

[tonyt1234563]

Hi Folks,

I am new to the BMW world, I have now owned a 328 for about a week. Unfortunately I got an error on the BMW computer and am having some trouble interpreting it. I have been tinkering with my lotus Esprit for years and enjoy it as a hobby, so hopefully this is the right forum for me for this car.

I bought the Peake Research scan tool, and the code I got was 11, 53, dc. According to the manual this means table 11 codes 53 and DC. There is no Code DC in any table and code 53 is crankshaft sensor. I also borrowed an orb II scan tool and it tells me the problem is oxygen sensor side 1 sensor 2 which seems more realistic of a diagnosis considering it has near 100k miles.

Is the Peake research tool reliable or should I typically go with the orb II? Has anyone seen similar conflicts? Also, which sensor is side 1 sensor 2? I assume this means post catalytic converter, but is it also drivers side?

Thanks!
Tony

[funkymarcus]

I assume the CHECK ENGINE light is lit? If not, you might just reset the fault codes and see what happens. Since you've only had the car for a week, there's no telling what odd things might have been done to it recently.

Could DC have been 0C (zero-sea) instead? The Peake tool shows "d" in lowercase. As you say, DC isn't listed in the M52 table. (I didn't check the Peake booklet, but I don't see it in another M52 table.) 0C would indicate the throttle position sensor.

The Peake tool is as reliable as the engine control computer in the car itself, it simply "dumps" what it finds in the computer. If you went to BMW and asked them to pull the fault codes, they'd give you the same results that the Peake tool does (although the numbers may be in decimal as opposed to the Peake tool's hexadecimal). I prefer it over a generic OBD2 tool.

"Side 1 sensor 2" sounds like the regulating (before catalytic converter) oxygen sensor for cylinders 4-6. Your OBD2 tool should have given you a P-code, such as P0139 - with that code, someone can nail it down for sure. I wouldn't expect the OBD2 tool to show an oxygen sensor fault without the Peake tool also leading you to that path.

If you have to replace one pre-cat oxygen sensor, I'd suggest replacing both. They're probably the same age and although the other one might not have generated a fault yet, it's probably close to the outer limits of its tolerances. I replaced both pre-cat sensors in my 328is last week, after reading E5 and E6 with the Peake tool.