W203 Gearbox limp mode

[Damien Joseph]

Dear peeps,

I brought a w203 c200 kompressor recently.

The car seems to be stuck in one gear most of the time. When I stop and restart the issue seems to be fine.

I was asked to change the oil, then wheel speed sensors and also tps and throttle magnet. Still the issue remained.

Initially there were no fault codes related to TCM.

The fuse no. 58 40amp fuse was blown. I replaced it however no power seems to be coming to the fuse.

On a scan it would show 420a fault. When cleared everything seems to be okay.

And again the next day morning the gear seems to be stuck.

Any advice?

 

[Damien Joseph]

Dear peeps,

I brought a w203 c200 kompressor recently.

The car seems to be stuck in one gear most of the time. When I stop and restart the issue seems to be fine.

I was asked to change the oil, then wheel speed sensors and also tps and throttle magnet. Still the issue remained.

Initially there were no fault codes related to TCM.

The fuse no. 58 40amp fuse was blown. I replaced it however no power seems to be coming to the fuse.

On a scan it would show 420a fault. When cleared everything seems to be okay.

And again the next day morning the gear seems to be stuck.

Any advice?

 

[John Laidlaw]

Morning and welcome...
I've no idea what code 420a is, not recognisable to me anyway.
You need a scan via Star preferably (as Mercedes and Mercedes independents use). What's your location we can probably recommend someone for you?

 

[Damien Joseph]

Morning and welcome...
I've no idea what code 420a is, not recognisable to me anyway.
You need a scan via Star preferably (as Mercedes and Mercedes independents use). What's your location we can probably recommend someone for you?

I'm from Sri Lanka

 

[Damien Joseph]

I'm from Sri Lanka

420A the speed comparison of Y3/6n3 or Y3/6n3 is implausible
4500 the transmission has an implausable transmission ratio
4502 the gear is implausible or the transmission is slipping

 

[John Laidlaw]

whoops apologies no-one in Sri Lanka I can think of!

 

[davemercedes]

Hello and welcome, Damien

Do you have "specialist" garages in Sri Lanka? In UK we have a lot of Independents (we call them "Indys") and a few are members on this forum.

If you were here in UK we would be saying that

1) the conditions you describe suggest that your car has gone into "limp" mode (which is designed to let you drive home but hopefully prevent serious damage) and

2) you need to take it to a recommended indy who has STAR (that's the Mercedes electronic fault-finding equipment). A good indy will normally be experienced enough to to interpret the STAR messages and solve the gearbox problem.

Unfortunately we often find people are told "try this/fit that etc" and guesswork like that may or may not help but it can certainly be quite expensive! So really you need to either go to a Mercedes Dealer for a diagnostic check or find an experienced independent who has STAR.

I ran a quick search and found Merc-Stop who (at 144, High Level Road, Colombo 06I) - they describe themselves as the "preferred alternative" for Mercedes Benz service so perhaps they can help you with diagnosis?

I hope you manage to get it sorted soon.

 

[mersum1es]

Check there is no oil in TCU or Transmission connector plug.
Check oil level of transmission is right (when changed last time?)

 

[Damien Joseph]

Hello and welcome, Damien

Do you have "specialist" garages in Sri Lanka? In UK we have a lot of Independents (we call them "Indys") and a few are members on this forum.

If you were here in UK we would be saying that

1) the conditions you describe suggest that your car has gone into "limp" mode (which is designed to let you drive home but hopefully prevent serious damage) and

2) you need to take it to a recommended indy who has STAR (that's the Mercedes electronic fault-finding equipment). A good indy will normally be experienced enough to to interpret the STAR messages and solve the gearbox problem.

Unfortunately we often find people are told "try this/fit that etc" and guesswork like that may or may not help but it can certainly be quite expensive! So really you need to either go to a Mercedes Dealer for a diagnostic check or find an experienced independent who has STAR.

I ran a quick search and found Merc-Stop who (at 144, High Level Road, Colombo 06I) - they describe themselves as the "preferred alternative" for Mercedes Benz service so perhaps they can help you with diagnosis?

I hope you manage to get it sorted soon.

Thanks a lot mate

 

[Damien Joseph]

Check there is no oil in TCU or Transmission connector plug.
Check oil level of transmission is right (when changed last time?)

No Oil in TCU and the connector plug. Last changed 2 weeks ago.