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I recommend to let your garage cancel the error, it is probably related to your battery since the PAS might have communicated wrongly when it didn't receive enough power. If it comes back it is more worrysome. I think it's safe to take the error away so your dashboard light goes off.

Thanks for that, racin'skoda! I totally agree, sometimes you just have to keep on. If nobody benefits from my thread right now then it might be somebody later! It's always important to follow up a story and finish it. The times I've had to read a forum post with the exact same problem, only to find the thread suddenly dying out half way... It's the worst! Unfortunately I wasn't very lucky with buying parts because it turned out that the refurbished pump I got from eBay was ALSO faulty. The lesson learnt is that sometimes you can't cut corners and buy used/refurbished parts from shabby places for cheap prices. Because of this I replaced the sensor and this was probably not necessary. In total this set me back an extra £400/500. The car went through the MOT today and the pump works! Finally! Looking forward to drive it. In addition to the pump the garage noticed a wheel bearing had gone as well as a rear suspension spring that had snapped. So I told him he could just replace both, I can't be bothered doing more work on it myself.

Well, actually I'm having some interesting developments the past few days. I had almost given up and sold it, then I suddenly saw somebody selling a "Factory New Pump" on the local Norwegian eBay. I thought I'd give it a try and it looks like it's working! The car is at the garage today getting MOT, fingers crossed. Looks like your pump is dead completely. Try getting it off the car and open it to see the electronics.

Good point, but the new sensor came with new wiring. So the wiring from the pump to the sensor were replaced.

So. I'm still having big, big troubles with my PAS. Problem: No power steering at all. Dashboard warning lights up. Attempts to fix it: - Check fuses - Check negative battery lead - Check alternator wire - Removed spongy wet pump jacket - Install refurbished pump - Install new sensor (metal) We are still getting this error on the VAG: "Implausible signal". Anybody has any idea? According to the Skoda workshop, there is no programming required when installing a new pump in this Fabia I (2003).

And the story continues. We have installed a new (metal) of sensor and I still have the "Implausible Signal" error in VAG. SO ANNOYING! We've replaced the pump (refurbished from eBay) and sensor but the problem persists. We have also checked the alternator lead and although it's tight it's not broken. The negative battery lead is fine too. Sometimes, within a week or so, the battery is suddenly drained. So we thought perhaps we have a current drain. Sometimes we measure 200mAh drain (high!) but other times we measure 20mAh drain (normal). According to an official Skoda workshop, this model pump does not need to be programmed with the car. Can anybody confirm this? At this point I'm lost. Does anybody have any tips?

Are you sure the link is right? It leads back to my own post. How do I program the pump? I have a VAG cable

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

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.

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.

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.

I'd like to contribute to this thread after having a whole lot of trouble with my PAS lately. The seperate thread is here, but to cut a long story short: One morning, PAS light came on, no PAS. No previous history of PAS problems. Read the OBD with a VAG cable, no signal from sensor, weird low voltages from pump. Checked sensor, seemed fine. Removed the foamy jacket, which was soaking wet. After some weeks, PAS light disappeared, still no PAS. Read the OBD, now voltages were normal and a normal signal from the sensor. Removed the pump from the car, dismantled it and found a blown voltage regulator. Appearantly, water and salt had entered the pump through the silicone seal due to the foamy jacket holding moisture and then destroyed the electronics.

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.

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?

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