Using Automatic B-Class as a Manual to override transmission fault

[Rainbowgirl55]

My ECU is causing all sorts of issues when I drive and I need to take it to be repaired. If I put it into Manual mode, will this override the ECU issue and let me drive it without issues to the garage 8 miles away (as long as I can shift gear at the right time!)?

 

[wongl]

Sounds like your car is in limp mode and as such it switching to manual mode will not over ride the transmission fault/error.

Is your car a B-Class W245 with a CVT transmission by any chance?

 

[Rainbowgirl55]

Hi, it's B class, 2010 plate and if I read various articles online correctly, B class does not go into limp mode. It just has "Transmission fault", I can turn the engine on with no problems, but as soon as I start driving on automatic, it has no clue which gear to go to, so it's very jerky and feels unsafe, especially in lower gears/slower rides. It is CVT and I guess W245 (Wikipedia says that number is linked to 2010). Sorry, not very good with cars. Had to go on a steep learning curve in the past 10 days! Workshops think it's ECU fault, I just need to get it to a workshop.

 

[Benzowner]

Pretty sure a 2010 is a W245 with the CVT box, I drove mine quite often in manual mode. It works like a paddle shift but on the gear stick. But if it's an ECU problem, I am guessing you will still have the same problems in manual.

 

[GLK]

It's not like there's an actual manual gearbox - it's only imitation, and for CVT a pretty fanciful one at that.
If the transmission is faulty, driving the car to get it fix might exacerbate the problem ...

 

[Rainbowgirl55]

It's not like there's an actual manual gearbox - it's only imitation, and for CVT a pretty fanciful one at that.
If the transmission is faulty, driving the car to get it fix might exacerbate the problem ...

Makes sense. Thank you very much for replying.

 

[wongl]

Hi, it's B class, 2010 plate and if I read various articles online correctly, B class does not go into limp mode. It just has "Transmission fault", I can turn the engine on with no problems, but as soon as I start driving on automatic, it has no clue which gear to go to, so it's very jerky and feels unsafe, especially in lower gears/slower rides. It is CVT and I guess W245 (Wikipedia says that number is linked to 2010). Sorry, not very good with cars. Had to go on a steep learning curve in the past 10 days! Workshops think it's ECU fault, I just need to get it to a workshop.

Yes, a 2010 B-Class is indeed a W245 with the CVT gearbox. The W245 most certainly has limp mode (as do most modern Mercedes cars). Is there an orange engine like symbol lit up on the dash by any chance?

The W245 CVT (which is identical to the W169 CVT) has a common design fault in the gearbox ECU which is immersed in gel and located inside the gearbox. It is common for the wires inside the ECU break off causing the ECU to lose connection to the RPM signal. To make matters worse, the broken wires often make contact intermittently confusing the ECU.

Get the error codes read to determine if this is the case. If so, the transmission ECU can be repaired for around £500 to £600 by a good indie. MB garage will probably try to sell you a new CVT gearbox costing several thousands of £££.

Stevenson has done this repair on a couple of my W169 previously so it might be worth giving them a call.

 

[Rainbowgirl55]

Thanks wongl. I found somebody to repair ECU for a bit more than you quoted, but still much cheaper than MB. I had it towed over the weekend to an indie. Fingers crossed, it all goes ok.

 

[wongl]

Thanks wongl. I found somebody to repair ECU for a bit more than you quoted, but still much cheaper than MB. I had it towed over the weekend to an indie. Fingers crossed, it all goes ok.

Good luck - the ECU repair by ECUTesting (with a lifetime warranty) costs circa £240. This together with a CVT transmission oil change circa £250 comes to circa £500. Add a few quid for secure postage to ECUTesting.

I don't want to worry you, but there have been horror stories of incompetent repairs to the CVT ECU out there. I would not entrust my ECU repairs to any old garage. ECUTesting no only gives a lifetime warranty, but members of several forums have used them with good experience. For myself, I found their work (cutting open the ECU casing professional, plus the return packaging to be excellent and cannot be faulted.

Good luck with your repair.

 

[manojs888]

Good luck - the ECU repair by ECUTesting (with a lifetime warranty) costs circa £240. This together with a CVT transmission oil change circa £250 comes to circa £500. Add a few quid for secure postage to ECUTesting.

I don't want to worry you, but there have been horror stories of incompetent repairs to the CVT ECU out there. I would not entrust my ECU repairs to any old garage. ECUTesting no only gives a lifetime warranty, but members of several forums have used them with good experience. For myself, I found their work (cutting open the ECU casing professional, plus the return packaging to be excellent and cannot be faulted.

Good luck with your repair.

Hi, these prices you quote for labour I haven't found anyone to be able to match by far, are you able to provide details of who could do this near the cost, pls

 

[wongl]

Hi, these prices you quote for labour I haven't found anyone to be able to match by far, are you able to provide details of who could do this near the cost, pls

Where are you located?