Hello,

 

I'd be very grateful if anyone with more knowledge than me can shed light on what might be causing an intermittent power steering failure on my 2010 Fabia 1.2 Tsi. 

 

Some background info on the problem -

 

• Starting from cold in the morning, PAS works as it should nearly every time, but not always
• If starting from hot (i.e I've switched the engine off whilst waiting in traffic) the power assist essentially never comes back on upon engine start. Sometimes it kicks back in within a minute or so, but not always.

 

• If driving with the PAS light on, when I come to halt (engine still running) the light usually goes out, but PAS is still inactive
• There's been several occasions when driving that the PAS light isn't illuminated, but the power assist isn't working either
• No codes/errors stored that the local garage can see on their diagnostics. 

 

Looking for any advice/pointers before the whole system gets pulled apart and rebuilt...!

 

Thanks

Tim

How old is your battery?

 

Check battery voltages with engine both running and stopped.

have you checked the fluid level.....................

Thanks for the swift suggestions!

 

I haven't measured the battery voltages, will do that. Though the battery (and alternator) are ~5 months old and the car spends most of it's life doing 30 mile journeys so hopefully ok.

 

Fluid level - I haven't checked this yet either - is it plausible a low fluid level might cause this intermittent behaviour?

/\ Those, or a fault with the steering angle sensor, most likely with the narrative "Steering angle sensor - implausible value".

The fluid is about 1/3 of the way up the narrowed section of the dipstick, which from reading around seems to be ~acceptable.

 

Battery voltage with engine off = 12.6v

Battery voltage at idle = 14.3v

 

No fault codes visible by me or the garage when they looked (steering light was illuminated whilst codes were scanned) 

 

I didn't have any power steering today. It's strange that the light goes out when the cars stationary, but comes on when the car starts moving. This could even be just when I'm stopped on a hill (light goes out, but PAS remains off) and then lift my foot off the brake and roll forwards - when I get to ~5mph the light comes back on (still no PAS)

 

Does this give anyone any clues as to what might be wrong?

Ok, you need to check the fusible links on the battery box, look carefully for damage or cracking.

All looks ok to me on the fusible links. From the diagram I have, the power steering fuse is the right hand most one (looking into engine bay) and I undid that nut - all bright with no corrosion underneath, and continuity shown on the meter... hmmm

Seems like pump or angle sensor could be next candidates for investigation - from what I've read there's no simple way to diagnose which is responsible though?

Angle sensor will give a fault code, pump unit failure will probably not.

As a follow up for anyone interested, it was the pump itself. Bought one from a breakers, swapped it and all appears good