I have been having problems with a recurring Check Engine Light. I have disconnected the battery and it goes out, but comes back on after abour 150 miles. It just passed emissions for state inspection with flying colors also.

I took it to Autozone to get a readout of the fault codes, and they said they could not read an 1995 SL, because it didn't have the OBDII. Is this true? If it doesn't have OBD, how does a mechanic determine where the problem is coming from? I'd rather not take it to the stealership, and wanted to get an idea of what the issue was before taking it to a mechanic.

Any suggestions?

OBD II started appearing on US sold cars in 1996 (I think). Your car should have OBD I though.

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As indicated by Schumi OBDII was mandatory in the US beginning with the 1996 model year. There were a few cars that got it early in 1995 MY. Of the MB stable, only the 201 chassis got it in '95.

I'm only familiar with the diagnostic system on the 124 chassis, but I expect that your car has a system unique to the Bosch KE injection system. There are only 10 codes and they are read via duty cycle from the ignition module diagnostic connector.

There are other diagnostic codes that flash a code, but they are not engine related. I would do some research here to ensure that this is correct for your car.

Do a search on maybe; diagnostic codes, check engine or DTC.

Good luck and Merry Christmas,

HI Larry! Word on the OD forum was that you had left for good!

95 R129 requires the ODB I connector.

THe R129 computer stores fault codes and retains them despite battery disconnect...so that won't work. You need an ODB I tool to clear the codes.

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A 95 Sl320 should have an M104.991 engine with the Hot-wire airflow meter - there should be plenty of information available from the computers in the car if you can find a scan tool that is capable of talking to them.

Many 1994/95 M104 engined MB's were ODB2 compliant even though the law didn't take effect until 1996. Just look under the "under-dash" cover on the drivers side, IF you see a rectangular electrical plug then you can use a generic ODB2 scanner.

That engine uses a "hot-film" air mass sensor not a "hot-wire" system! Plenty of live data.

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