- Intermittent Steering Malfunction -

[1BrokenMerc]

My car is 8 years old with about 24000 on the clock regularly serviced by non MB garages. Having just travelled about 250 miles then did a short trip of about 2 miles shortly after. I was attempting to spin my car around at a wide junction, on full lock applied, when the steering failed and up came the "Power steering malfunction - See owner's manual" on the dash. I struggled to drive back the 2 miles with extraordinary heavy steering. The following day I was looking for the cause when I discovered the warning message had disappeared and the steering was functioning as expected. A short drive later with nothing like full lock applied I'm in trouble again. I shut down the car - turned off lights etc and the power steering functioned again.

Couldn't get a dealer to look at the problem for 3 to 4 weeks and I needed to do the return journey within the week - oh b----r!

I now have the vehicle home and want to exploring if the issue might be something straightforward to fix.

Certain it is unlikely to be:
+ related to the vehicle battery;
+ a fuse problem;
+ a grounding problem;
+ a software issue.

I think it may be a steering rack fault since wiggling the steering wheel results a light clunking noises - like worn teeth on a pinion are riding over mating parts.

I see 'used' steering racks online so was wondering:

can the steering rack be easily removed and replaced without the need to reprogramme anything?
am I likely to be able to acquire and replace parts in the steering assembly?
am I looking at the issue fro the wrong angle?

Any pointers/suggestions please folks?

 

[alexanderfoti]

Before you spend any money, you should read the fault codes in the steering module, to track down what codes caused the message to come up.

 

[1BrokenMerc]

Before you spend any money, you should read the fault codes in the steering module, to track down what codes caused the message to come up.

Thanks for the prompt what you suggest is always a good starting point. Interestingly my scan tool did not reveal a fault code when probed. Inappropriate scan tool capabilities perhaps or maybe warnings only produce proprietary/non-compliant codes a more sophisticated scan tool would read.

I complained at the last service/MOT that there was an occasional knock on the steering when turning which went unresolved 9 months back. I'm thinking this issues experienced recently are related.

I did find another thread where a MBO member suggested that the 'thrust piece" is worn so I'll explore this route first. Fingers crossed this could well resolve the faults experienced.

Regards.