CLS320 CDI Limp Mode / No Kickdown - OM642

[DanB8]

Hi Everybody,

This is my first proper post and it's a big one so thanks for bearing with me.

I have a few problems with my new to me CLS 320 CDI. I'm new to diesels and Mercedes so any help would be greatly appreciated and sorry in advance for the long post but IMO detail is key.

The car is a 2005 CLS 320 CDi - Full Service History (few dealer when newer, mainly Mercedes specialist DEY in Birmingham) - 150,000 Miles.

I changed the oil over the weekend and overfilled it by 1.5L (owner manual stated 10.5L - I put in 10L). Checked dipstick and the oil level was all the way to the top of the red gauge. I assumed that the oil wasn't fully around the engine so let it warm up then took it for a short steady mile drive.
The EML came on. I knew something wasn't right so checked on the forum and people say 8L to 8.5L for the OM642. I drained out 1.5L and thought nothing more of it as the EML went out and the car felt great.
I used genuine Mercedes 5w30 - 229.51 oil and a genuine Mercedes filter for the service.

Went for a drive on Sunday and the car went into limp mode with no kick down or power and the EML came back on. The gearbox felt awful. Whilst it still changed through the gears it didn't change smoothly.

I read the codes yesterday and I had quite a few pop up.

2032-1 Check component G3/2 (02 sensor upstream TWC). Voltage is too high.
2078-2 Check component b28/8 (Pressure differential sensor (dpf)). The signal voltage is too low
2080-8 Check component B28/8 (Pressure differential sensor (dpf)). Dynamic offset of component
2082-8 Check component B28/8 (Pressure differential sensor (dpf)). Plausibility error due to defective hose lines.

I also took the inlet/maf sensor to check if any oil had blown up the breather - There wasn't any but I found this but will post about this separately.

OM642 Turbo Inlet Seal Installed Incorrectly

• DanB8
• Oct 18, 2017

I brought a replacement and changed the item, deleted the codes and the cars performance was restored (full power with kick down and smooth shifts).

Today, the EML is back on, I've read codes and have

2032-1 Check component G3/2 (02 sensor upstream TWC). Voltage is too high.
2078-2 Check component b28/8 (Pressure differential sensor (dpf)). The signal voltage is too low

Has my DPF had it? Or is it more likely the pressure sensor? Are these problems because I overfilled it? Or just a coincidence?


TLR I put too much oil in car, drove for 6 miles, EML came on, drained excess out, EML went off. Took for a spin on Sunday and now in limp mode with codes for DPF sensor, 02 sensor etc. Car feels rubbish - No power or kick down - Jerky gear shifts.

Any help at all will be greatly appreciated.

Dan

 

[DanB8]

Any takers

 

[Tuercas viejas]

Dan Hi & greeting perhaps I can help from afar!
I have looked over your post and my first question is since you seem to have a scan tool of sorts, can you read off live data on the tool?

P2032-01 is a bit confusing because it can refer to the shift module but on face value the Cat 02 sensor is stuck on high signal, so in short it's not switching!
due either to an exhaust gas condition or the sensor has aged to a point it needs replacement . Being an SOC Cat it needs oxygen remember to light up the cat! In short the gas is too dense with no oxygen present.
Now with any scan tool in generic or OBD2 Global you can confirm this fault since it will show P0133.

P2078-002 refer to the Differential Pressures Sensor. Connected to both sides of the DPF by steel and silicon rubber pipework hoses its reading restriction in HPa.
Obviously then pipework condition & gas tight sealing is essential for the sensor to read the DPF back pressure correctly. Check yours for security and deterioration.
This sensor looks like this:-
b28/8 pressure differential sensor sprinter - Google Search:

See if you can locate it and read off the part # of the body. There have been a number of suppressions on this sensor so it's best to call an MB dealer with the vin number of your car and see if its been replaced. In fact on this side of the pond there is even a new harness to improve communication.
So to reiterate see if you can read off some live data especially the HPa restriction on the diff pressure sensor & EBP (exhaust back pressure sensor).
Regards T/V

 

[DanB8]

Hi Tuercas and thank you for your comprehensive reply. I have learnt a lot from it.

I do have a scan tool. It's an Autel MaxiDiag Pro MD801. It has the generic OBDII scan area and specialised manufacturer area that can read the following modules.

CDi4 - Engine Control Unit
TRANSMISSION
SBC - Brakes
ESP - Stability Control
AB - Airbags
CGW - Central Gateway Control Module

It also reads live data but not O2 stream or Back Pressure etc. I will check and come back to you with what it does have on the live data side.
I have scanned the car on the Mercedes setting today (CDi4 Module) and the fault code for the O2 sensor has disappeared as:

2032-1 Check component G3/2 (02 sensor upstream TWC). Voltage is too high.

But has emerged as:

P0132 O2 Sensor Circuit High Voltage Bank 1 Sensor 1 - SCANNED ON OBDII

Similar but different and strange that it isn't being picked up in the CDi4 module. I'm also getting a new fault code:

P1400 EGR switchover valve output stage (Y31-1) - SCANNED ON OBDII

The fault code 2078-2 Check component b28/8 (Pressure differential sensor (dpf)). The signal voltage is too low - Still remains when I scanned the CDi4 module today.

I'm worried that the O2 sensor and DPF sensor are both OK and that it is the DPF being clogged that is causing the sensors to throw a fit due to back pressure differences? Is this possible?
I'm going to check the signal voltage on the DPF sensor because I believe that if the signal is 0.0v then the sensor is likely faulty but if it's 0.23V for example, it would mean the sensor is working and it's picking up a drastic/quick change of pressure hence the fault code. This I believe would mean the DPF is likely clogged. I will get the part number, check all the lines and call Mercedes to find out about updated DPF Sensors. Am I on the right track??

It's interesting that you mention the upgraded wiring to aid communication as it tells me the original system was flawed but it's so strange how all of a sudden these problems came on after I changed the oil and overfilled. I've also attached the decoded build sheet incase it will help.

Checking VIN for Mercedes-Benz WDD2193222A043471 | CARInfo

Thanks again Tuercas

Dan

 

[DanB8]

Hi All,

Just a quick update to say the problem has been solved by changing the DPF sensor. There are no fault codes present and the car pulls nicely with kick down and smooth gear shifts. The codes for the O2 sensor have disappeared too. I think the reason the O2 sensor fault code came on is because the ECU could see that the signal from the DPF sensor was telling it there wan't any oxygen in the exhaust gas (no signal voltage) but the O2 sensor was saying there is oxygen in the exhaust gas. The ECU has then assumed there is a problem with both the O2 and DPF sensor because the information it was getting from each sensor contradicted each other. I'm not a mechanic so I could be totally wrong but it seems logical to me but please don't take it as gospel and if someone knows that I'm wrong please let me know.

Anyway, I checked the voltage at the pressure sensor and I didn't have no voltage showing on the signal line which told me the sensor had failed. The sensors themselves have been superseded a few times. As Tuercas mentioned, find out the part number on the DPF sensor fitted to your car and call up Mercedes with your vin and let them check if it's been updated. I fitted a new 'updated' one (£49.70 from Merc) and cleared the fault codes before starting the car. Jobs a good un.

For other's who may be having the same problem here is what you need to check for when testing the power going to the DPF sensor.

There are three wires which are:

Live - 5V
Signal - O.23V E.g. The sensor is working because it's sending a signal to the ECU.
Ground

The slight signal voltage is used by the cars ECU to determine how full the DPF is. It uses the pressure difference of the exhaust gas before and after the DPF to get it's reading on what condition the DPF is in. It sends this info to the ECU as a voltage reading. Once a certain voltage is met the on the signal wire car will regen when conditions allow.

My readings were:

Live - 5V
Signal - 0V - No reading at all says the sensor is not working.
Ground

If your signal wire does show a reading and the fault code (2078-2 Check component b28/8 (Pressure differential sensor (dpf)). The signal voltage is too low) still remains it could indicate that the DPF is clogged and needs regenerating, cleaning or replacing. Again, I'm no mechanic so please do your own research before committing to a new DPF because of what I said.

All in all I'm well chuffed that it's back to normal again and it cost less than £50.

The old DPF sensor part number is A 007 153 61 28. New one is A 642 905 01 00.

Thanks Tuercas for pointing me in the right direction.

Dan

 

[Tuercas viejas]

Dan glad to read you fixed it!
It makes me wonder how many souls have paid out for new DPF's when all that was needed was a new Diff Pressure Sensor or defective connection pipework.
Confirm part A 642 905 01 00. is the latest and greatest even on this side .
So for you the instant accolade & a well done on the codes --You speakamy language!

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Tuercas viejas

 

[DanB8]

Thanks Tuercas,

I'm so relieved it solved the issues as it could of been a big bill. I have wondered myself how many people have replaced DPF's, O2 Sensors, EGR Valves or even gone to the trouble of deleting the system and mapping it out out of the software when it could well be a cheap sensor.

I have another quite shocking fault that I found today. Maybe you could cast your eye over it if you have a second.

Thanks again for your input mate.

Dan

 

[Tuercas viejas]

I have another quite shocking fault that I found today. Maybe you could cast your eye over it if you have a second.
Oh me gawd what now ?

Does it need a Catlick Irish Blessing !!
Take a gander at this !! Priceless!

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Tuercas viejas
aka Dennis

 

[Parkl]

Hi, I see thread is not new,
but anyone have a number or link to find a new harness for better communication between Ecu and sensor?
Thx