I have a 1995 C280. It only has 116,290 miles on it. I scanned my car and this is what I got:

P0305 misfire cylinder 5
P0400 exhaust gas recirculation flow
P1170 short term fuel trim malfunction
P1700 up-shift delay switchover valve without function (logic chain)
P0325 knock sensor 1 circuit (bank 1)
P0306 cylinder 6 misfire
P0302 cylinder 2 misfire
P0300 random misfire

I don't have an owners manual so I don't know where anything is on my engine. Does anyone have a couple diagrams of the C280 engine and other parts? What could cause the Misfires in only cylinder 2,5 & 6? I tried finding someone with the same problems in the forums but I couldn’t find anything really close. Does anyone have a suggestion on where to start?

Thanks for anyone who can help!

Megs

 

in your case ur engine is a sright 6,first of all check the wiring which goes onto the coils this models do safer on the engine wiring special which goes on to the coils they gethard and break,thats the reason you gettin various fault codes......this is first thing i would check the whoule of the harness.........let me no hw u get on...

 

Hi,

I agree with Naz but would first cancel the codes and then go for a run to see what returns.

With so many codes present it would be helpful to know which is the "main" code.

The key is probably the P0325 Knock sensor CIRCUIT. This is indicating something incorrect with the resistance of the circuit atstartup and could be wiring or the sensor.

I would also ensure your fuel is good before spending money on replacement parts

Stuart

 

My boyfriend and I looked at my car and tested the Coil Packs on his Audi A4, so he helped me do it on my car.

The coils all seem to be fine. There was no change.

I was reading that the vacuum pump controls some modules or something on the older Mercedes. Mine use to make a really loud noise, like it was trying to work, and someone said it was a leak somewhere. I could hear where the leak was but I couldn't pinpoint the leak to which hose. Then one day I just stopped hearing the pump working at all and now my doors and dome lights don't work.

Could my vacuum pump be the problem?

The person who owned my car before me died, so his wife just let the car sit in their garage since 2003. I bought the car at an auction so I bought a fuel filter, oil, oil filter, and replaced those things and the spark plugs. Now it is running even worse.

I dropped it off with my younger bro today to see if he could help. He called and said he thinks it could be a million things.

 

Thanks for your help by the way.

 

You testedthe coil packs. How?
Checking thatthereis a sparkj is not enough since unless there is a spark the engine would not run at all.

The doors are operated by a PSE pump which is usually located in the boot. Your doors not locking AND dome light ON is a classic symptom of the PSE gone bad BUT the dome light not working does not usually occur with a pump that doesn't run at all. Its usually associated with watergetting on the contacts of the unit.

You need to start at the beginning.

Ensure you have a good battery. (i.e. Car cranks and starts OK with the headlamps on.)

Record then CLEAR/RESET the DTC codes. A garage will need to do this if you don't have a scanner.

Go for a short run and see what you have.

If nothing go for a longer run etc.

Report back results and we will try to help further.

Stuart.

 

My younger brother, my boyfriend and I finally figured out what was wrong when we put our heads together. But now there is still a problem...

The problem was that when I replaced the spark plugs it was in the dark cause I get home from work late. So I didn't put the coil packs on correctly, and apparently with all of the checking and opening the top lid thing on my engine to reach the spark plugs, someone ended up stripping the holes that the screws go in. So the lid didn't sit tight on the engine and I am guessing it has to so that the coil packs are tightened and not loose.

So after I went to a junk yard and tested the coil packs (long story too long to explain how I did it), I noticed that it was loose, so when I got home my brother and boyfriend ended up re-lining or whatever the wholes so that the screws fit. Then I looked at a diagram, placed the coil packs and wires back correctly and now my engine doesn't shake like it use to.

I checked the battery and it seems fine.

Here is my new problem:
I hear a little rattling from the serpentine belt, which I have been reading that you should replace your pulley or the tensioner when you replace the belt. I can't get the serpentine belt off cause I have no clue what is what and what to unscrew!

The next problem is that as I was driving home from work, and clearing the codes, the CEL came back on. So I scanned it, and cleared it and drove to work and home again the next day and it came on again. The code I got was P1170. Which read: Short term fuel malfunction.

What is that?

Also I checked all of the interior lights for water and I even took them off and whiped them down. They still don't work. I hear this intermitten clicking coming from under the steering wheel right by the door, under the dash basically.



Thanks for all the help!!!

Megan

 

P1170 is not a standard OBDII code but your car is 1995.

P1170 (manufacturer specific) is as you state Fuel trim. This means thatthe computer can't achieve the correct mixture. MOST LIKELY its the MAF OR the O2 sensor OR BOTH but many other things COULD also cause this problem.

Problem is both components are moderately expensive. Sure you refittedthe air cleaner etc correctly? i.e. No leaks.

Search under these topics on the forum for more info. Both easy DIY jobs (no coding) if they are the cause.

Stuart.

 

I have a mercedes C280 1995, I've had problems with the two middle coils misfiring, having changed all 6 coil packs and replaced the spark plugs, I still had problems with shuddering and shaking occassionally when idling. I had a mechanic check they were installed properly and not faulty they were all correct. He suggested it could be the ECU, if I just plug in a new ECU do I need a code, or can I reset the Ecu myself. If anyone can suggest anything else maybe regarding the sensors that are given information by the Ecu can you advise please.
Regards
00 Blonde