I have a problem with my 2007 TDV8 Vogue.

The power steering is heavier than it should be (and compared to my other TDV8 vogue). Had the car a month and issue has been there since I bought it (it was very cheap so couldn't say no).

Symptoms:
Steering is heavy regardless of engine speed
Road speed seems to make no difference (although less noticeable at higher speed due to less steering input required)
Very occasionally, the steering will be light after start up but not managed to link it to any other event that would cause it to go light
Sometimes when starting, the instrument cluster turns off for a split second and then goes through it's start up procedure when the engine is started. Not sure if this is related

Things Tried:
New servotronic valve
New BCU (or GEM as they are known on the 07MY).
Hours of internet forum searching.

I understand that on models up to 2007, the servotronic valve was controlled by the BCU and would open and close depending on a speed signal the BCU got from the ABS ECU. However reading the 2007MY workshop manual, the BCU has now been renamed the GEM (general electronics module) and the description of it's function makes no mention of the Servotronic valve. I was hoping to find some wiring diagrams to confirm that.

One other 'specialist' said the steering column joints may be stiff, but that doesn't explain why it would go light occasionally.

I'm unsure if the quirky instrument cluster is related or not, it could cause a CAN BUS fault, but on the 06MY the speed signal from the ABS ECU to the BCU was hardwired and did not use CANBUS, and the servotronic valve was hardwired to the BCU so cant see that would cause the issue. One person on the web fixed their instrument cluster with a new ignition switch (was only providing 9v output on the switched live during cranking hence the instrument cluster went down, cranking power to the engine was 12.6v).

I will check the ignition switch this weekend, but dont hold out hope of that fixing my steering issue.

Anyone have any ideas, or come across the issue before? There is a serious drink (or cash alternative) to anyone that comes up with the solution!!!!!

Thanks in advance

Neil

i had a number of issues and one of them was heavy steering at times also would not self center at times
sorting out the other strange issues (intermittent suspension faults ect) led to replacing alternator ,
the battery tested ok so never replaced at that point ,the steering got better but not 100% (never put 2+2 together at that time)
eventually got my FBH plumed in and working but scrapped the battery doing it
replaced battery for a 110A and no more heavy steering also cured a first turn of the key click from the starter
happy days
dont under estimate the importance of a charging system and battery in tip top condition on these things

under powered battery = pain int the ass ff

i was going to suggest the servotronic valve but you've replaced that already...i would double check that the sensor cable going to the valve is making a proper contact though..
have you checked the fuse in the gem?

@Stan - Thank you. Fuse in the GEM? Did not know that. Will check.

Where did that diagram come from? I have the 07MY workshop manual but at >1000 pages I may have missed something.

@ironhorse - Battery was load tested and was perfect, alternator also providing expected voltage. If all else fails I will take the battery out of my other 07MY and see if it helps.

the fuse appears to be in the gem or it could be the fuse in the fusebox that powers it, not sure..

diagram is from the WM neil, link in the wiki.. ... - .- -.




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Got it - page 536 of 3104

stan wrote:

the fuse appears to be in the gem or it could be the fuse in the fusebox that powers it, not sure..

I reckon it's in the fuse box, as the diagram shows it's hardwired to the GEM, not installed in the GEM. Else it would also suggest the servotronic valve and the ABS module are also inside the GEM