C270 CDI running in Emergency Mode after adding Redex

[abeatty44]

Hi, I'm hoping that someone can help me.

I recently input some diesel redex fuel system cleaner into my 2005 C270 CDI into a full tank. Initially when I put it into the car after a few miles the Engine management system light came on and the car went into emergency mode - only runs in 2nd gear. However, after switching off and on the car the light remained on although the car was no longer running in emergency mode.

After about doing another 160 miles in the car since the redex was added today I topped up the tank with fuel and initially the EMS light went out. However after doing about another 20 miles the light came back on and the car went into emergency mode again and remained in 2nd gear. I have had to drive the last 40 miles like this unfortunately - switching on and off makes no difference on this occasion.

Any idea why the EMS light would come on because of adding redex diesel fuel cleaner? Also, is this problem lightly to resolve itself once the redex is out of the system or have I a bigger problem?

Thanks

 

[Twistedmind]

I have always used redex and millers with no problem.
I don't think that's your problem. You need to get the codes read.

Check your maf for dirt.

Sent from my iPhone using MBClub UK

 

[abeatty44]

I brought the car to a independent mechanics today who stuck it onto the computer. He said that the reading shows an error with the Crank Speed Sensor but this could also be a gear box issue.

He recommended that I bring this to a Mercedes main dealer to get fixed. So I have the car booked in at Merc tomorrow. I'll provide an update once I have it.

 

[Lord-WYBMAnE220]

Fill the tank and change the fuel filter.
Might just do it.

 

[abeatty44]

I brought the car into Mercedes who confirmed that the issue was the speed sensor. They cleared the fault code and the car was running fine again for about a month.

The issue re-occurred again yesterday so I bit the bullet and decided to get the part replaced.

Question - The independent dealer said that the part was the Crank Speed Sensor, whereas Mercedes said the issue was the speed sensor. Are there different speed sensors in the car or are they referring to the same part. The symptons are that the car will only run in limp mode and the EMS light comes on the car.

Merc quoted me the guts of £1,000 for parts and labour.
The independent quoted me £120 for the part, still waiting to hear labour cost but suspect that it will be much less than at Merc.

 

[panason1c]

The crank sensor (fitted between the engine and gearbox joint) when faulty, will cause the engine to stop, there is no 'inbetween area', it either works or it doesnt.....the usual symptom when faulty is that it faults when it gets hot from engine heat and refuses to let the engine run, then, when it cools down it will allow the engine to start again.

The gearbox 'speed sensor' (located within the gearbox) when faulty locks the gearbox in limp mode, a restart usually restores function but after a few restarts the limp mode then becomes fixed until the speed sensor is renewed and the codes cleared from the ecu.

Sounds like your problem is the latter, though I'm not sure you should see an engine light for this fault

Can't see redex being responsible, just a coincidence?

 

[BlackC55]

I think you have both faults.

 

[abeatty44]

I got the crank sensor replaced - issue still exists.

This is exactly my problem currently:

The gearbox 'speed sensor' (located within the gearbox) when faulty locks the gearbox in limp mode, a restart usually restores function but after a few restarts the limp mode then becomes fixed until the speed sensor is renewed and the codes cleared from the ecu.

Merc quoting close to £1,000 to replace this. Any cheaper options?

 

[BlackC55]

Go to a specialist like me.

Maybe we could recommend on near you?

 

[jaymanek]

The electrical plate replacement along with a transmission service is £500 at an indie!