No Power Steering (PAS)

[JvdP]

So it's been a few weeks now without power steering. I've tried several simple things but I've come to the point where I need some help. Any advice is welcome.

Skoda Fabia 2001 1.4L (AQW) with 125.000 km on the clock.

After a few cold weeks here in Norway (down to -13 degrees C) I started the car in the morning and the PAS light came on. No functional power steering. I tried turning the car off and on, same problem. No history of PAS problems with this car known.

Tried to look at the fuse box, no visibly broken fuses. One strange thing, according to this online manual, terminal 5 is supposed to be the PAS (50A) but that terminal is empty in my car. I have a red/green wire on a 40A fuse on terminal 6, so I suppose this is the PAS.

Ordered a VAGCOM cable. Tried the cable and got the following information

Before ignition Fault Codes

01288 - Terminal 30; Steering Assist

07-10 - Signal too Low - Intermittent

Before ignition Measuring Blocks

After ignition Fault Codes

00566 - Steering Assistance Operation

27-00 - Implausible Signal

01288 - Shareware Version. To Decode all DTCs

07-00 - Please Register/Activate

After Ignition Measuring Blocks

Interestingly, the voltage on the terminals is lower when the car is running. Not sure what the normal voltages are for these terminals (12v I suppose?) but I'm not even sure where I can find these in the car.

Any ideas of whats wrong here?

[Avalon]

Check the fuse location and replace the fuse for the tiny amount it costs to be sure, a hairline crack is sometimes hard to spot, then do the same with flat fuses on top of the battery compartment (under the false lid), the PAS fluid level (under the battery box), the earth point on the battery and the chassis, the battery itself (cold tends to kill them off if they're on the way out), the connections to the PAS pump then replace the steering angle sensor. That's pretty much the route I took, I'd add if the PAS fluid is low then check for leaks but if it's fine then don't waste your time.

[JvdP]

Thanks Avalon for your input. I did actually check the fluid level of the PAS the day after it stopped working, I forgot to mention that in the startpost. The level was below the minimum. When I'd put in the dipstick, the dipstick would JUST reach the oil level and get a little wet, but it was under the minimum. So I topped up, but no change.

The fault codes by Ross-Tech:

01288 - Terminal 30; Steering Assist: Signal too Low

00566 - Steering Assistance Operation: Implausible Signal

The combination of these 2 together makes me think it's a connector/fuse problem and not necessarily a broken pump unit, what do you guys think?

Similar problems/topics:

Power steering Failure - Can I still drive it?

VAG COM Scan Results

I have the following action plan:

1. Check Fuses
   I'm aware of the possible hairline crack. I'm planning to take out the fuse and have a look at it. I'll buy a new one after the holidays.
   
2. Check Battery
   The battery seems in great condition. The indicator (green) says its healthy. I have a newer, 47Ah battery lying around. I know this is too small of a battery but I might give that a try just to see.
   
3. Check PAS fluid level
   Was low, but topping it up didn't solve the problem.
   
4. Do a diagnostic check
   Results in the start post.
   
5. Check/Replace Negative Battery Lead
   
6. Check the steering angle sensor
   
7. Check the the alternator wiring (ref.)
   

Edited 23 December, 2012 by JvdP

[JvdP]

So, I've been lying under the car again, no luck. I checked fuses, battery leads, the pump itself and the steering angle sensor. I'm not sure how to measure whether the pump/sensor are dead. How do I do that?

Anybody has an idea what's wrong here? I still find it strange that the diagnostic measured less than 12v at the pump...

Fuses

I took some fuses out, they looked perfectly fine to me. Didn't replace them (since I didn't have any spare) but I can't see how this can be the problem. Here is a picture of it.

Battery

The battery seemed in great condition. But just after christmas, when the car had been standing still for some days, it ran out of juice as I was trying to start. It was way too low on capacity. So I bought a new one and mounted it. It starts like normal again but it didn't solve any problems regarding the PAS (I even cleared the diagnostic errors).

Negative Battery Lead

Seems fine, but should perhaps replace it to be sure? I live in Norway and it's not easy to get parts.

Steering angle sensor

Man, can I just start off saying that this thing is quite hard to get to?! So when I finally got it out it seemed fine, no traces of water or something. it's the G250 TRW with fixed cable and it's part number is 6Q1423291. It's plastic and not aluminium, so does this mean that I have the notorious plastic one? I read here that it is a common failure, but it didn't seem to have water in it.

Pump

This was quite a job to get to. The RHD version has the wiper liquid reservoir around the pump, so this has to come off together with the bumper, battery and air filter.

The plastic around the pump was completely nackered, very very brittle. The sponge around the pump was totally soaked. I left both off. Perhaps this caused a short and killed the pump?

[Avalon]

My pump plastic was exactly the same, the plastic cracked as soon as it was touched, if it were in tact it would have held water as yours was, the pump was fine though as it constantly kicked in/out. Check you are getting 12v (usually slightly over from memory) at the pump using a multimeter, if you are and it's doing nothing then its most likely the pump, they're horrifically expensive new so it's probably better to source a used part or a cheap new part.

I noticed that my PAS pump was in a constant state of flux as though I was moving the wheel fractionally left/right so I knew my pump was getting voltage, I'd previously removed/cleaned the sensor with no luck so I ordered a replacement as the sensor as my pump was obviously working I figured the sensor was misreporting the wheel position and causing the pump to kick in/out all the time. It's been 10 months and 16k and it's not missed a beat yet.

If it were me i'd get a multimeter on the pump, with the sensor, you have the plastic version that's known to be defective, sooner or later you'll be changing it, after rebate the genuine part is about £70, the earth lead you can eliminate by bridging the negative to an unpainted surface.

[JvdP]

Thanks a lot for the detailed reply again Avalon, it's well appreciated! I agree with what you say. I should have measured voltage at the pump yesterday! I've put it back together again since I don't have a dedicated garage. Taking it all off again is a hell of a job, I tell you. Not difficult but just the amount of hours that goes into it.

I've looked on eBay.co.uk a little bit and they are indeed really expensive! http://www.ebay.de/s...os&_stpos&gbr=1http://www.ebay.de/s...os&_stpos&gbr=1 are even more expensive. The cheapest used units I could find go for about £100 + shipping and in my case you can add 25% tax to that. I'm lucky if I can find this part in Norway for cheaper.

Anybody an idea about the compatibility? I'm pretty sure I have a TRW, but that's about all I know. I couldn't see any official VAG part number on it, only a bar code with a weird number that doesn't give any hits on Google.

Anyway, if it's not the power, it's either the pump or the sensor. How do I find out which one it is? I suppose that when the pump is dead, the sensor won't read a signal either since it goes through the pumps ECU. But in case the sensor is broken, the pump won't do anything either. So I'm having a hard timing choosing which (expensive) component I shall replace first.

Edited 6 January, 2013 by JvdP

[blackie63]

i would love to know what the part number is for the steering angle sensor in my y reg 1.4 mpi fabia estate as the information plate is missing in the car :( e mailed a guy last month on ebay with reg and vin said the one he was selling was correct then the lisitng changed and now its not the right part confused here :(

[fabdavrav]

Get the steering angle sensor from your local Skoda dealers........................and yes you have the original "faulty" plastic one. New improved type has a much smaller goldy coloured metal cap to it. Also make sure that you take your old sensor out carefully as when you buy the new one from the dealers you should be able to get a "refund" of about £25 for the old one.........well I did when I did my car and my mates 1.4MPI!!!!!

[JvdP]

Get the steering angle sensor from your local Skoda dealers........................and yes you have the original "faulty" plastic one. New improved type has a much smaller goldy coloured metal cap to it. Also make sure that you take your old sensor out carefully as when you buy the new one from the dealers you should be able to get a "refund" of about £25 for the old one.........well I did when I did my car and my mates 1.4MPI!!!!!

Thanks for the feedback fabdavrav! Is this the new improved type? I suppse not, since I don't see any goldy coloured cap, but it is metal though.

[JvdP]

i would love to know what the part number is for the steering angle sensor in my y reg 1.4 mpi fabia estate as the information plate is missing in the car :( e mailed a guy last month on ebay with reg and vin said the one he was selling was correct then the lisitng changed and now its not the right part confused here :(

On my sensor, it was on the side. It was not easy to see, since it was molten/carved in. See my photos.

[fabdavrav]

Thanks for the feedback fabdavrav! Is this the new improved type? I suppse not, since I don't see any goldy coloured cap, but it is metal though.

Looks like it........it's the sort of gold/yellow pasivated flat metal top to it that the cable comes out of!

[vgnils]

My 2002 Fabia was equipped with the KOYO power steering system. The pump failed and since the pump is no longer manufactured, the solution from Skoda is to convert the power steering system into the newer TRW type. More on this here: http://www.briskoda....-steering-pump/

It's crazy expensive - I hope you dont't have to go down that route...

By the way, your local dealer should be able to tell you which system is installed in your car?

Edited 12 January, 2013 by vgnils

[JvdP]

I'm pretty sure it's TRW. The product number of the pump/system can be read by diagnostics (see screenshots).

No dashboard light!

Today I had a weird experience. As it is saturday, I finally had time to look at the car again. So I started it, no steering light. What?

I drive it every day to work and back, I've seen the steering light not going out even a second (well, the times when the started motor turns don't count) and now it was suddenly gone!

Intermittent power steering

Still no power steering when parked, though. So I started driving around a bit and noticed that I got some power steering when I start crawling. I don't think it's 100%, but I can feel something at least. I'm really not sure, I was just really confused.

I hooked up the diagnostics again and measured a bit. I get a healthy voltage readout this time (no more low, weird voltages) both with and without the engine running. Also the sensor is now clearly reading a signal, that seems correct!

On the other hand, still no power steering when the car is stationairy and the diagnostics also don't show any power (amperage) going to the pump. At least something is happening. Is it perhaps the wet, damp sponge that I removed from the pump and now it finally has had time to dry up? It's started to get dryer, but colder again this week...

Fault Codes

Ohja, and I'm still getting some fault codes (even though no lights coming on dashboard). First I had:

00566 - Steering Assistance Operation

27-10 - Implausible Signal - Intermittent

Then after clearing it I got:

00566 - Steering Assistance Operation

27-00 - Implausible Signal

Diagnostics

Here's some screenshots of the group diagnostics:

Doing a short drive through the public garage:

Turning all things (heated seats, wipers, window heating, high beam, electric windows) on, then off again to see how they affect the voltage.

[JvdP]

Looks like it........it's the sort of gold/yellow pasivated flat metal top to it that the cable comes out of!

It has the exact same part number so it should do... Perhaps I could get it on a good deal.

[JvdP]

I have bought a remanufactured pump on eBay and now waiting for it to arrive. Not sure what programming I need to do to get it working but we will see. Any tips on this?

Edited 1 April, 2013 by fordfan

[JvdP]

So, this easter I've spent my days in a dark garage while the weather outside was phenomenal. The result: a disection on the pump.

The good news is that I found the problem but the less good news is that the money I spent on a remanufactured pump is already spent.

After getting the pump off the car, it took some occasional brute force to open the unit. As most of you know and also mentioned in Haynes, this pump is a so called "unservicable" part apart from changing the reservoir. Of course, there's not much stopping 2 curious engineers from looking what's inside.

We tore away the silicone seal around the bottom housing, then it slid off and the pumps internals were revealed to us.

What you see is three sets of connectors coming into the pump (one set between each torques screw). From right to left: the sensor, the power supply and the communication with the ECU. The big cylinder on the top is the rotor of the brushless electric motor.

It didn't take long for us to discover what had gone wrong. On the lefts side, one of the voltage regulators had blown.

There was a lot of strange looking deposit on the walls inside the pump. It's either oxidised something (aluminium?) or salt, of which the latter seems more likely since they salt the roads here in Norway extraordinarily much.

My theory is simple:

• A lot of snow, salt and low temperatures attack the pump.
  
• The foamy jacket (originally meant for noise isolation) worsens the situation.
  
• Moisture (with salt) eventually makes it into the pump.
  
• Destroys the electronics (the voltage regulator) and makes the pump seem dead.
  
• I remove the foam jacket, the pump starts drying.
  
• Part of the electronics springs back to life, the PAS warning light on the dash disappears and the sensor passes its value through the OBD again.
  
• But still no power steering due to broken voltage regulator.
  

Such voltage regulators are usually easy to find and from the looks of it, it seems like an easy soldering job. I just have to take the pump a little further apart so I can reach it. Perhaps I could give it a good inside clean while I'm at it.

Edited 1 April, 2013 by JvdP

[snaler]

Wow. great detective work! and really useful pictures.

If my charged battery doesn't solve mine, I am encouraged to try this.

Thanks!

[JvdP]

Wow. great detective work! and really useful pictures.

If my charged battery doesn't solve mine, I am encouraged to try this.

Thanks!

You're welcome.

The disassembly of the pump from the car is rather easy and straightforward. On my model (LHD) I had to take the bumper off and uninstall the wiper fluid reservoir, but all in all just a few hours work.

Then, dismantling the pump might seem a daunting task at first, but if you know what to do you can get to the goods rather quickly. You might think you need to take off the reservoir, but this doesn't help. Also, don't be fooled by the torx screws holding the connectors, because they won't get you inside the pump either. You have to start prying open the silicone seal, then pull off the aluminium cap and voila, there's the electronics.

[snaler]

Well, I finally solved my problem with a new pump (from the scrapyard!)

I did manage to open the pump (with a chisel and a screwdriver - a bit like taking a tyre off a bicycle - you just have to work it round)

I didn't take the bumper off, I did it all from inside the wheel arch, just removed the plastic arch liner (RHD)

Did you manage to get the circuit board out? I couldn't see a way to remove the impeller to get at the screws to remove the circuit board. My local electronics shop said you need to see the back of the board to really identify failed components.

I didn't have any obvious burnt out components like you did.

Anyhow, all my faults - 1288 signal too high, 1290 short to plus, short to ground, implausible signal - they all disappeared with a new pump.

I think the controller for the power steering is inside the pump. The only way I can think that VCDS reads 18volt at the pump is that the 5v signal to the sensor is being put across the negative terminal of the pump. The electronics are screwed inside there.

So, in short, there seems to be little value in opening up the pump....

Correct me!

Now I just hope I don't need a new rack as well...

[KenONeill]

There was a lot of strange looking deposit on the walls inside the pump. It's either oxidised something (aluminium?) or salt, of which the latter seems more likely since they salt the roads here in Norway extraordinarily much.

That looks very much like the sort of corrosion we experience here inside those sort of cast aluminium cases to me.

[JvdP]

So I have a status update. We have managed to dismantle the pump so we can read the MOSFET identification number!

It was a bit of work to get the rotor off but not hard. I think getting the circuit board out is rather impossible, some contacts seem to be spotwelded and the circuit is very integrated.

Interestingly, when I googled "buk9508 PHm003" I had only 1 hit. It's from a Romanian VW website about PAS problems with somebody who has the exact same problem. I ended up ordering 5x BUK9508 from eBay for $7,60 there were quite a lot on there. I'll let you guys know when I've replaced the broken mosfet.

[JvdP]

That looks very much like the sort of corrosion we experience here inside those sort of cast aluminium cases to me.

Is it because of water/humidity entering the pump?

Do you think it's bad to leave it there or can I just assemble everything after I fixed the electronics? It's quite a lot of work to get it out.

[KenONeill]

Is it because of water/humidity entering the pump?

Do you think it's bad to leave it there or can I just assemble everything after I fixed the electronics? It's quite a lot of work to get it out.

Water and salt. It's quite a crumbly substance, but it's a aluminium salt, and those actually make anti-corrosion protection themselves.

[JvdP]

So, I got the pump (refurbished, from eBay) installed and... Same problem! Wow, this is annoying.

2 Faults Found:

00566 - Steering Assistance Operation

27-00 - Implausible Signal

01288 - Terminal 30; Steering Assist

07-00 - Signal too Low

Also, the voltage reads 7,7v in the diagnotics. This is strange because before I switched the pump, this voltage seemed normal.

Is the sensor broken after all, causing the pump to fail? I'm not getting a read on the sensor, like I used to be able to.

The wiring was measured and there was no resistance through them, although that's a rather simple check.

Any ideas?

[f1reblade]

When you change the pump it needs to be programmed , I read this here -> http://www.briskoda....s/#entry3059551

Spoke to the VAG shop today, and they say the unit needs to be programmed. So going to the workshop tomorrow and give it a go. Fingers crossed

My problem is the same with PAS and lights flickering (on every 3-4 seconds maybe), when PAS light is on, lights and dashboard stop flickering. Changed alternator relay, but old one was ok, don't know if new one caused problems, but since i've changed it, started problems with revolutions - up and downs, battery is new, but i don't drive very often, any ideas? My sensor is plastic one, no water in it, checked fuses on top of battery, earth ...

multimeter shows from 13,2 to 14,6 (can't remember exactly, but big difference every 3-5 seconds)

sensor error was smth like G250 open or close to plus?!

help pls

(fabia 1.9 sdi 2003)

Edited 29 May, 2013 by f1reblade