Any chance someone can help me out on the specifics of this diagnostic code;
I have been experiencing hard starts for the past few weeks and today got a check engine electrical warning. I was able to retrieve the diagnostic code of P1386 which is listed as the knock control. I reset the code however, I'm sure I still have the same condition.

Specifically, what and where is the knock control?
Do I need to replace the knock sensors?

Thanks for any help.
Col B

I'm not intimately familiar with the V8 cars, but I understand the generalities of troubleshooting the knock sensor.

You can easily check the knock sensors IF your car is such that you can put on a timing light. With some of the newer ignitions with individual coils you can't put on a timing light.

The basic is that if you hit the block with a hammer in the general area of the knock sensor, you should see the timing retard. This is easy to test on engines where you can indeed use a timing light.

Hope this helps,

I had a problem with my E320 stalling and sometimes it wouldn't start if warm. It ended up being the knock sensor. I saw no DTCs with a simple scanner, but my mechanic caught it with his scanner after several visits. He also contacted a MB factory rep. about the problem. The MB rep. said that they are seeing more knock sensors fail on the older w210s.

I was only charged 1hr labor for diagnosis and replacement, so I imagine it isn't too hard to replace. I never found out where it was located though.

__________________
1998 E320 120K mi
1991 Miata 80K mi
2001 Ranger 109K mi

That code doesn't mean that anything is wrong with the car most times! What it does mean is that the engine timing is being retarded to the MAX amount, about 12deg! POOR quality fuel is the most common problem even if you are "paying for" preminum 91 octane fuel! Carbon build-up in the engine can also cause this problem.

For 50+ years MB NEVER recommended any fuel additives but they do now suggest THEIR additive MB number 000-989-25-45-12. However I would try Tectron or another "aftermarket" cleaner.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

MB Doc,
Thank You.

I discussed this with a Mercedes Master Tech and he suggested several possible problem areas;

- Might be the lower engine harness as these have proven to be problematic in the past in terms of cracks in the wires which might cause erroneous fault indications
- Might be a fuel pressure problem causing the hard starting
- Might be the knock sensor

Also the reason for the P1386 fault code is due to the OBDII code reader being a generic reader and not MB specific.

Do you have the Ohm values for the knock sensor?
What about the voltage for the wiring harness at the sensor.

BTW, they are located under the engine mounts on the 210's

Generic Or factory scanner the code means the same thing!

That code has nothing to do with a faulty knock sensor!

ALSO the wiring harness problem was resolved as of 11/95 production.

THAT code means that the computer has at times retarded the ignition timing to the MAX!

Yes a faulty fuel pressure regulator can cause hard starting.

Sounds like the tech you discussed your problem with isn't up to snuff with that code!

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator