Electro-hydraulic power steering fault

[dandyman1]

Hi all. Just to update you on this problem. after another diagnostic and a full wire connectivity check i decided on getting a second hand unit. i managed to get one delivered for £125 all in this was a good price as most were asking for £250 ish.
I put the pump on and all was resolved. steering is sweet as and better than i had ever had it!
This proved that the recon/repair had not been successful.. I duly asked for a refund and low and behold i got one in full! This i was grateful for
but it took so long and so much stress and hard work not to mention additional costs for diagnostics.. oh well lesson learnt.

I must admit i have learnt alot about EHPS pumps in the process!! and the van in general and overpriced repair services that dont always work.

If you do need to change the pump your self it is quite easy so dont be afraid to have a go. note there are 3 types also. so make sure you have the right plug connection. also if they are second hand you wont need to have it coded to yr van as i was led to believe!! only new pumps need coding. if i had known this from the start i would have just bought a second hand pump!

Thanks for all involved. I hope this thread helps someone else. as most of the info you may need is here..

[myglaren]

Pleased to see your problem resolved.

[david0116]

I have a totally different fault to any I see online....
Power steering is very light I can do full lock from one side to the other with 1 finger even when stationary. I've replaced the electric power steering pump the steering wheel angle sensor and its still the same. Mechanic said the rack looks fine, just very slight play, no leaks. I put it on my diagnostic device and it shows that even though the van is idling at 768 rpm, and it shows that the electropump assembly motor is pretty much red lining constantly. Any ideas??

[xantia_v6]

It kinds like it may be a faulty torque sensor, which is probably located in the rack on the pinion shaft.

[david0116]

Cheers mate, I'll check that out

[david0116]

Before I start, is the torque sensor the same as the steering wheel angle sensor? I have already replaced that?

[xantia_v6]

I may have been mistaken about the torque sensor. I have not been able to find any reliable documentation describing how the pump speed is controlled, it could be controlled by a torque sensor (as I assumed), or it could be controlled by measuring the pressure and/or flow rate at the pump. Do you know if the steering rack itself has any electrical connectors? If there is an electrical connection near the pinion housing, there is likely an electrical torque sensor in the rack..

There will in any case be a torque sensitive hydraulic valve in the rack, inside the pinion housing, and if the torsion spring fails, then that will cause 100% steering assistance, which seems to be what you are reporting. If that were the case then a replacement rack would be the only course of action. With the vehicle switched off, is there any detectible rotational slack if you wobble the steering wheel from side to side?

[david0116]

I've given up and sold it now. The rack wasn't electric., just a standard rack which looked OK just had very slight play, no leaks. The pump itself was replaced. The same problem was still there. I was hoping to keep it but needed a vehicle for work and its been off the road for a couple of weeks already. Thanks for your help anyway