Hey everyone,

Ran into an issue earlier today with my 99,000 mile 05 C230SS. Had my A/C on AUTO with recirc, stopped at a traffic light, and noticed the car started idling pretty badly. I'll notice this occasionally, especially with the A/C on, but never this noticeable. RPM gauge wasn't bouncing, but it was a rougher idle than normal.

Got on the freeway and I could barely get the car up to speed. When flooring it, the tranny kicked down and the RPM's jumped, but the car wouldn't go faster than 40MPH. Eventually, I got it to 50mph. I pulled to the side of the road, shut the car off, removed the key, restarted it, but no difference.

Once I got to my destination, I decided to run thru the throttle reset. Let the car sit off for about 45 minutes, and on the way home it ran perfectly. This was about a 9 mile trip. I then took it to AutoZone to have them pull any codes. My CEL was already on because of a P0128 code (thermostat, which I'm just about going to order one to replace). In addition to the already known P0128 code, AutoZone pulled 2 more:

P0340 - Camshaft position sensor (CMP) "intake" circuit
P0238 - Turbo/Supercharger boost sensor "A" circuit high

From AutoZone home (about 4 miles), the problem was fine until the last mile or so, where it wouldn't accelerate past 30 MPH. Since I wasn't on the freeway, I didn't feel it necessary to push it past this.

My gut feeling is that it's the Camshaft Position Sensor that's reading bad, and causing the car to go into limp home mode. I've read on the forum that it could also be the timing that slipped a tooth, but my thinking that it's not my case is because on the longer drive home, it ran with no issues.

The other issue I noticed is that when I start up the car, the engine cranks and starts, but there's not the usual "oomph" that normally happens at startup. Tough to explain, but the best way would be during a normal startup, the engine might initially rev to about 2k RPM right at startup, then settle down to around 1K or so. Now, when it starts, it barely hits 1K, and then remains around there. It even sounds quieter during the non-normal startup.

I read thru a bunch of older posts with this issue with the M111 engine, but not too much for my M271 engine. So before I start throwing parts (and money) at the problem, I figured I'd bring it up here.

Any thoughts and suggestions?

Thanks so much everyone.
Cintoman

 

Paul ~ The car seems not to be engaging high idle for cold start Cat warming.

I would change the thermostat and Cam sensor. Cancel all codes & see what happens.

You might have to get the car onto a Star or something that can read transmission codes. You might be storing a transmission code as well to trigger limp.

Good luck!

 

Thanks for the info Glyn. I just went out to cold start the car right now. And now it won't even start start !!! The engine/belts turn, but it doesn't crank over like a normal turnover. It does make a smooth noise, but not the "chug-chug-chug" of a cranking over.

It's about 81F (27C) degrees outside, so it is pretty warm. I unplugged the Camshaft Position Sensor, started it, but same results. No oils or any residue on the connectors.

I already ordered the sensor and the thermostat. Hoping for it to come in soon.

Any ideas on this new issue? Weird how even though it would go into limp mode yesterday, at least it still started. Almost sounds as though there's either no spark or no fuel going in. Would the Camshaft Position Sensor really cut the spark and the fuel to the engine?

Paul (Cintoman)

 

CPS (crankshaft position sensor) or pump/filter problems or both.

Check fuel pressure at the Schrader valve on the front fuel rail. s/b> 3.8bar or 55 psi while cranking.

Strange all these gremlins suddenly????

 

I put a regular stick-style tire pressure gauge on the Schrader valve on the fuel rail and had a neighbor start the car up while I held the gauge down on the valve. With it squirting some fuel out while cranking, I was able to get 35psi coming out of it. I'm thinking if I had a good gauge (one you can screw into the valve), I'd probably come close to hitting the 55psi.

So it doesn't seem to be fuel pump-related. Could there still be a clog in the fuel line? Or could it be the crankshaft position sensor that's cutting the fuel and the spark? It's cooled down a little bit now...75F (23C).

Thanks again,
Cintoman

 

Ok, so the parts came in today, and I just replaced my Camshaft Position Sensor. Started the car up, and it's still doing the same thing.

Could it be the Crankshaft Position Sensor? But unlike other posts with the Crankshaft that's bad, with the car cooled down, theirs would start up. Mine doesn't.

Was going to replace the thermostat later this afternoon, since this has caused my CEL to be on for quite a few months now. Going to wait until it's cooler outside. But I don't think replacing it will make much of a difference in the startup issue.

Cintoman

 

Just for clarification. Did you replace the camshaft position sensor or the camshaft actuator magnet (front of engine)? People use the camshaft position sensor interchangeably on this forum.

You could have a crankshaft position sensor failure. They don't always work when they are cold.

Start enable fuses are 31, 52 & 57. 52 is obviously OK or it would not crank but check the others.

 

Hi Glyn,

No, I didn't replace the variable camshaft actuator magnets on the front of the engine, but rather the camshaft position sensor (Bosch Part #: W0133-1939117) on the top of the engine, visible once you remove the plastic engine cover.

Yeah, I know what you mean on how they're spoken interchangeably here. Makes it a little confusing.

I checked fuses 31, 52 & 57, and they're all fine.

I ordered a Crankshaft Position Sensor last night, which should be in by Monday. My issue now is trying to find where this sensor is located on my M271 engine.

I found WIS document AR15.12-P-2133QK (Remove/install crankshaft position sensor), dated: 3.2.09, but the included pic in the document (P07.04-2102-01) seems to show a view of the engine removed. Because, I think without removing the air box and MAF, I don't think there's any way to get at the sensor from above. I haven't gone underneath and removed the undershield from my car yet, so perhaps once I do so, it might be more apparent and accessible. In fact, the document does step you thru doing this underneath the car.

My other concern is with the final step indicating having to "Conduct sensor adaptation in ME control unit using STAR DIAGNOSIS". Will I have to get whacked by the stealership with a diagnosis hookup to complete this?

I've included the PDF for reference purposes.

Cintoman

 

Paul I just saw your post in the thread about the timing chain. Where you posted the video of your noisy startup. It's been 6 years now, but if memory serves there was some sort of TSB on camshaft sensors on the rear of the engine. Mine were replaced due to being extremely noisy on start. They never caused it to fail me, but the car only had 35000 miles at the time.

Did you ever get that noise diagnosed?

 

Hey Matt,

A little less than a year ago I went up to EAS (European Auto Solutions) in Waltham, MA, a good 1 hour away from me, based on all the positive reviews I've heard from them on this Forum. Ed, the owner is a great guy over there.

They diagnosed my noisy startup problem to potentially be the camshaft adjusters. Replacement of each of them (2), along with the timing chain, since everything would be already opened up, was to have run me, I believe, around $2,000.00+. At that point, I wasn't able to cough up that kind of money for the repair.

It just so happened that this was right around the time where I'd have to do an oil change on my car. And usually, around this time, this would be when my car would come up with a "At next gas station, add 1 quart engine oil" message. It hadn't come up yet, but the oil level on my car was probably almost at the point to add 1 quart to it.

I ended up changing my oil using one of those MityVac fluid evacuators, and noticed that whatever I was able to extract was quite a bit less than the oil level spec; so it was a bit low, even taking into account that the MityVac wouldn't fully extract ALL of the oil from the engine.

After replacing it with new oil to the correct amount, the noise definitely went away at startup. So I attributed it to less oil in the car, and since there was less oil, there's even less so up by the camshafts, causing the louder startup noise. Since then (September 2013 or so), the noisy startup has happened maybe about a 1/2 dozen times or so.

Since I've had the car (I purchased it with 13,025 miles), I never had the camshaft sensors on the rear of the engine replaced. I don't remember a TSB on it, but I'm definitely going to check for it now.

Cintoman

 

Yes adjusters. Those were replaced on my car under warranty for a similar noise. It was nasty. But lucky for me I had warranty at the time. I found the TSB during my research for "WTF is wrong with my Mercedes" but that's been so long ago I can't remember where I found it.

 

So my Bosch Crankshaft Position Sensor came in today, and I spent over 3 hours just trying to remove the old/bad one from the car. Man...what a pain in the *SS it was trying to put a socket on it to remove it. There was a thick wiring harness smack in the way, that I could not move aside to get a clear opening to remove it. I eventually rigged a screw driver bit, the external torx socket, a small extender and a wrench to finally remove it. What a pain.

Then came the moment of truth...tried to start it up, and, to my dismay, the same startup sound as before....engine/pistons moving, belts spinning, but no cranking/starting. WTF. I would have bet that it was definitely this sensor.

Which now brings me to the question of what the hell else can it be? Currently, I'm actually charging my battery via one of those box charging units you plug into your home power/electricity. The car lights come on, so it's not indicating that the battery is dead, but Glyn had mentioned to me previously that codes can come from low voltage. Could it be that there's not enough juice to get the fuel pump to send enough fuel to the engine?

I also confirmed there are no OBDII codes stored on the car by checking using a standard OBDII code reader.

My other concern is with the final step that's mentioned in the WIS document for replacing the Crankshaft Position Sensor:

7. Conduct sensor adaptation in ME control unit using STAR DIAGNOSIS:
- Only when replacing crankshaft position sensor (L5):
- After replacing crankshaft position sensor (L5) the following steps must be conducted:
-- Connect STAR-DIAGNOSIS and select menu item for control unit adaptations in ME control unit.
-- Reset sensor adaptation of crankshaft position sensor (L5).
-- Afterwards accelerate sensor adaptation of crankshaft position sensor (L5).

Of course, I don't have a STAR DIAGNOSIS system, so I can't perform this step. But would NOT performing this still cause the issue, even though a new CPS has been installed? Would disconnecting the battery and reconnecting it work to reset the system so it recognizes the new sensor?

I haven't replaced my thermostat yet. This was the other thing that had an OBDII code come up. I don't think this would cause the car not to start up, being that I've been riding with the CEL for this issue for over 6 months, and I've had no problems with it. But I might replace it tomorrow afternoon. Since I was also going to drain and replace the coolant, I would have preferred to do it when I could start up the car and get it running, so as to remove any air in the system. But if you think it's worth doing the job now, I'll go for it.

Thanks again everyone.
Cintoman

 

If you already replaced the CPS, and still not starting, im afraid you have a fuel issues, did you check that...!?!

ZAYED,,

 

Hi Zayed,

I haven't specifically checked the fuel pump or fuel filters yet, but I did check for fuel pressure at the fuel rail, and there's definitely pressure there. Without replacing the fuel pump or associated filters, is there a way to verify if they're not working or bad?

I'm just wondering if I actually have to perform step 7 in the WIS document with the STAR Diagnosis system. Car might still think I have the old/bad CPS installed.

Cintoman

 

Hi Paul,

Sorry, i may missed something before,, is the car cranking but not starting or it's even not cranking..?

ZAYED,,

 

Hi Zayed,

Yes, the car is not cranking in the typical chug-chug-chug sound. But I can hear the pistons moving up and down and the belts are turning. It just sounds like there's either no spark or no fuel getting into the engine. Maybe I'll try and post a video in the morning to give everyone a better idea of what it sounds like when I try starting it up.

Thank you again.

 

Hey Everyone,

Here's a video clip I just took this morning of my car trying to start up. You can hear the pistons moving up and down and see the belt moving, but it's not cranking or turning over. Like I mentioned earlier, the Camshaft Position Sensor and Crankshaft Position Sensor have been replaced and CEL Codes have been cleared.


Cintoman

 

Thankss for the video Paul,

Did you check the fuel pump relay, or cut-off battery relay...??

ZAYED,,

 

Hi Zayed,

Would you be able to explain how to check these items?

Thanks.

 

Try to remove them & see is there are any sign of melting or burning, or bend in any of there pins...

ZAYED,,

 

Hi Zayed,

I believe the Fuel Pump Relay is located in the rear SAM, relay A. But not sure what the cut-off battery relays are. Could anyone confirm?

Thanks,
Cintoman

 

Paul,

In some version fuel pump relay & battery cut-off relay comes as one relay #: "002 542 11 19",

and some version comes as a separate relays, while you have U.S version, you should have on relay for both....

ZAYED,,

 

I checked relay A in the Rear SAM, and it's 4RA 007-813-00. Visually, it looks fine to me. No burns or bent/damaged pins.

Cintoman

 

I see, seems Everything OK, then 3 things left:-

"ECU or EIS or not enough voltage to the CPS ",

if there are a problem with (EIS)Drive Authorization, the key will not operate,,

you have to check the voltage goes to CPS, should get (2.3v) to fired up, if you get less than that, car will not start,,

ECU should to be adapt/reset to make CPS & SAM function properly....

ZAYED,,

 

Hello again Zayed,

I don't think it's a problem with the EIS, as it recognizes the key fine, and sends the signal to start the car.

I'm not sure how to check the voltage to the CPS. I'm not familiar with testing things like this, so I wouldn't know how to test for 2.3volts at the CPS.

When you mention to reset the ECU, I've searched the forums, and there's conflicting information. Some indicate doing the throttle reset at the gas pedal (key to position 2, step on gas pedal past the kickdown switch, hold for a few seconds, turn the key to off, and release the gas pedal). Not sure if this will do it or not, or if I should just disconnect the battery for an hour or so.

Thank you again.