SRS Fault Code on 1991 R129
 

I recently had a "Check Engine" light on my 1991 R129 (300 SL). I used a 12 volt LED and a ground wire to check the faults and hopefully reset them using the 16 terminal diagnostic port.

On terminal 7 of the diagnostic port, I have two unusual indications. The first is a permanent low resistance ground. The test lamp stays on, but dimmed, anytime the test probe is in receptacle 7. The second is that the "fault" does not clear using the usual procedure of grounding the test terminal for six to eight seconds. Anytime I check it, I get nine flashes of the test lamp which normally indicates something wrong with the SRS warning lamp or with the Code Scanner itself. Strangely, my attempt to clear this fault did clear the Check Engine lamp even though it didn't clear the fault code.

I will greatly appreciate any suggestion of the real fault or a reference to a really analytical diagnostic manual for the Mercedes using the 16 terminal diagnostic port.

Thanks,

Bob D

Check page numbered as 254 here: http://www.w124performance.com/docs/mb/diagnostics/DTC_Reference_Guide_Ed.B.pdf