[pussinboots77]

Hi all. I have a 2008 147 TS 2.0 Selespeed. I'm led to believe that the gearbox speed sensor is faulty as all sorts alarms and warnings are appearing. My mechanic advises error code P0720 is current. The question I have is how can I get to this sensor? I have read a number of threads and they talk about a brown cable connecting plug at the top of the engine. I cannot see this plug in my engine bay. Any ideas? I understand that the senor is mounted to the gearbox. Is it difficult to find and replace?

 

[David C]

Gearbox speed sensor or Engine speed sensor?

Gearbox speed sensor would mean it is a Selespeed, if you don't have a Selespeed, then you don't have a speed sensor in the gearbox.

 

[pussinboots77]

Gearbox speed sensor or Engine speed sensor?

Gearbox speed sensor would mean it is a Selespeed, if you don't have a Selespeed, then you don't have a speed sensor in the gearbox.

Yes, it's a Selespeed. Thanks for the question. I have updated my post.

 

[David C]

OK
I'm sure the gearbox input speed sensor is on the front of the gearbox, not far from the fill plug & reversing light switch.

The posts you've seen about a brown connector on top of the engine are for the engine speed sensor.

 

[pussinboots77]

I think I've worked it out. The sensor on my car has an integral plug connection ie. no wire attached.

 

[pussinboots77]

Ok, so I had the speed sensor replaced and all was well for a few months. Now I'm getting the same problem again. All sorts of messages are displayed and the vehicle cannot go above 2nd gear. Diagnostics reveal the same vehicle speed error P0720 as before. Any ideas why this error would be appearing again given that a new sensor was only recently installed?

 

[addo]

Exactly what dash warnings do you get?

 

[pussinboots77]

Exactly what dash warnings do you get?

Motor control fail, VDC fail.

 

[addo]

BazzBazz is possibly one person to ask about this, are you sure it isn't the ECU faulting internally? Also you could hit up Alfamotive if you're in Sydney. Andy has seen most failures several times and then some...

There's a thread in the GTA forum about ECU repairs where a good number of people have had the same component come loose in the ECU - it requires skilled miniature soldering to fix. I know it's a different ECU, but wonder if the faulty part occurs in both.