Afhussain

Hi,

I need your help, I have been an owner of a S500 (S550) for under a week and the car has now broken down.

It was driving fine, I was visiting some friends, left from their house and within a couple of minutes I got a message on the display in front saying "drive to workshop without changing gear" in red.

The car was still changing gear fine and I did not have any issues previously with the gearbox not changing correctly.

I panicked and pulled over to the side. Pressed the P button and turned the car off. Then tried starting it and now the car complains that it can only be started in either P or N. It seems it is stuck in D.

I have been googling the problem and have read stuff about low auxiliary battery voltage, IDM failing, gearbox selector unit failing and possible the whole gearbox failing.

Any advice you can give would be really appreciated. The first thing I need to know is where the secondary battery is located on by his car?

Afhussain

Put the car on the Launch computer and it is coming back with the following error related to the Intelligent Servo Module

Codes 1974, 1951 and 1939 are stored and current, the others are stored.

Any help would be greatly appreciated

1904
The internal mechanism in component A80 (Intelligent servo module for DIRECT SELECT) for engaging selector lever position P is not in the correct position.

1922
System shut down due to an internal fault in comment A80 (Intelligent servo module for DIRECT SELECT)

1974
Selector level Current position 'P' was engaged due to a fault occurring in component A80 (Intelligent servo module for DIRECT SELECT) or in the vehicle communications

1964
Fault during initial startup of component A80 (Intelligent servo module for DIRECT SELECT)

1951
Internal startup Of control unit in component A80 (Intelligent servo module for DIRECT SELECT) has not yet been performed

1939
No CAN message received from control unit Y3/8n4 (Fully integrated transmission control (VGS control unit)

Afhussain

Forgot to say, although the car thinks it's stuck in D it seems that it is actually in P. The car can't be rolled forward at all.

The engineer tried to relearn ISM but the relearning failed. We could hear it trying to move the gear selector but did not seem to be coming out of P.

Afhussain

Just in case this helps anyone else, I replaced the Intelligent Servo Module and the car is now starting and working fine

Atcpup

Thank you for following up! What year vehicle and how many miles are on it?

Afhussain

It's a 2006 with 87k on the clock. Now let's hope nothing else goes wrong

Shevon

What was the cost of the repair?

Afhussain

About £600

GelandewagenNub

Did you replace it on your own?