SL/R129: 300 SL OBD1 fault code diagnostic results
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Newbie
Joined: Aug 2013
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1991 Mercedes 300 SL
300 SL OBD1 fault code diagnostic results
Hi,
1991 300 SL with check engine light diagnosed to OBD 1 Socket 8 (Distributor Ignition) showing 17 flashes which on fault code table suggests Possible Cause of Failure to be "Crankshaft Position sensor faulty".
Also Socket 14 (Continuous Fuel Injection System - MAS Controller) reports 9 flashes which fault codes to "Circuit 50 failure". (note these return even after being cleared).
I'm non-mechanical but any suggestions on what to advise my non-MB mechanic to start looking at based on the above?
Thanks in advance.
1991 300 SL with check engine light diagnosed to OBD 1 Socket 8 (Distributor Ignition) showing 17 flashes which on fault code table suggests Possible Cause of Failure to be "Crankshaft Position sensor faulty".
Also Socket 14 (Continuous Fuel Injection System - MAS Controller) reports 9 flashes which fault codes to "Circuit 50 failure". (note these return even after being cleared).
I'm non-mechanical but any suggestions on what to advise my non-MB mechanic to start looking at based on the above?
Thanks in advance.
Newbie
Joined: Sep 2020
Posts: 9
Likes: 2
R129
Hello,
I know its been a while you posted this but I have the exact same issue.. have you manage to find what the issue was? Any help would be appreciated.
thanks
I know its been a while you posted this but I have the exact same issue.. have you manage to find what the issue was? Any help would be appreciated.
thanks
Hi,
1991 300 SL with check engine light diagnosed to OBD 1 Socket 8 (Distributor Ignition) showing 17 flashes which on fault code table suggests Possible Cause of Failure to be "Crankshaft Position sensor faulty".
Also Socket 14 (Continuous Fuel Injection System - MAS Controller) reports 9 flashes which fault codes to "Circuit 50 failure". (note these return even after being cleared).
I'm non-mechanical but any suggestions on what to advise my non-MB mechanic to start looking at based on the above?
Thanks in advance.
1991 300 SL with check engine light diagnosed to OBD 1 Socket 8 (Distributor Ignition) showing 17 flashes which on fault code table suggests Possible Cause of Failure to be "Crankshaft Position sensor faulty".
Also Socket 14 (Continuous Fuel Injection System - MAS Controller) reports 9 flashes which fault codes to "Circuit 50 failure". (note these return even after being cleared).
I'm non-mechanical but any suggestions on what to advise my non-MB mechanic to start looking at based on the above?
Thanks in advance.
Thread Starter
Newbie
Joined: Aug 2013
Posts: 14
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1991 Mercedes 300 SL
Sorry, nothing new to report since I have not driven the car this year (due to Covid). If you diagnose anything please let me know (and I will do the same).
Newbie
Joined: Sep 2020
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R129
Newbie
Joined: Sep 2020
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R129
I've never known of a cranskshaft position sensor to fail on a 300SL or 500SL.
You're supposed to read codes for the ignition system with the engine running. Otherwise, one consequence is that code 17 will unconditionally appear. Find more info here.
You're supposed to read codes for the ignition system with the engine running. Otherwise, one consequence is that code 17 will unconditionally appear. Find more info here.
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2017 GLE350 4MATIC
@MikeShields @Mike00135 I would throw new sensors at it, starting with the crankshaft position sensor. It's a 30 year old vehicle. Nothing, including sensors, lasts forever.
Newbie
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R129
@MikeShields @Mike00135 I would throw new sensors at it, starting with the crankshaft position sensor. It's a 30 year old vehicle. Nothing, including sensors, lasts forever.
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Newbie
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R129
any suggestions?
thanks
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Newbie
Joined: Sep 2020
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R129
I'd check the fuel mixture. To do that you'll need a multimeter. With the engine idling at a temperature greater than 40 degrees C. you first measure the voltage between sockets #2 and #3 of the connector located on the passenger inner fender. That voltage should fluctuate several tenths of a volt and be roughly 30% - 70% of the steady voltage measured between sockets #2 and #6. Next you switch the engine off and again measure the voltage between sockets #2 and #3. Now it should be steady and be 70% of the voltage you measure between #2 and #6.
appreciate your help.. thanks!
Newbie
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R129
I'd check the fuel mixture. To do that you'll need a multimeter. With the engine idling at a temperature greater than 40 degrees C. you first measure the voltage between sockets #2 and #3 of the connector located on the passenger inner fender. That voltage should fluctuate several tenths of a volt and be roughly 30% - 70% of the steady voltage measured between sockets #2 and #6. Next you switch the engine off and again measure the voltage between sockets #2 and #3. Now it should be steady and be 70% of the voltage you measure between #2 and #6.
Newbie
Joined: Jul 2020
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SL600
HI,
looking for find location for my cranskshaft position sensor , its very hard to find location , be side i have problem my left side engine, AIR MASS sensor , replace twice, by any chance can help me , if you have access to startek, information on my R129 v12, will appreciate
Mike
looking for find location for my cranskshaft position sensor , its very hard to find location , be side i have problem my left side engine, AIR MASS sensor , replace twice, by any chance can help me , if you have access to startek, information on my R129 v12, will appreciate
Mike
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