PAS problem

[KenONeill]

VCDS doesn't calculate the voltages, it simply reports what the PCM tells it, the onboard ECU will have accurate voltage measurement capability, it's very important for all the PWM controlled actuators and the throttle stepper.

That might be the case, or it might just derive the voltage from the actual clock speed.

[KenONeill]

Quote from firballxl5:- "So coming back on topic and this is only my opinion, having read not only on this forum but from other sources that electronic power steering is not reliable, or should I say its fine when working as it should, but when it lets go, it lets go big time and as your steering is one of your major components as to the running and safety of your vehicle, so do you trust your steering? From what I have uncovered there is nothing worst than driving along, with a knot in your stomach, waiting for your steering to fail."   

 

Well it could be worse, see the latest from Jeep etc!

 

I'm not sure that current(present) electric steering is any more reliable than this hydraulic assisted system, quite a few failures from Mini and failed columns from Fiat etc, as well as rack failures, normally the build regulations will demand that when the system fails, unassisted steering, though heavier, will exist. It is when we get braking by wire we will need to hope that someone has done their homework properly!

"Electric" PAS is actually a misnomer. Electro-hydraulic PAS would be better, since the electric part is an "on demand" motor supplying power to a hydraulic pump rather than the pump being directly driven from the engine accessory drive belt. Both systems still require a physical shaft between steering wheel and pinion (or steering box).

[Breezy_Pete]

I reckon the onboard supply control unit (J519) samples the battery voltage between that ground wire that fireball has discovered (going to connector XS4/pin 8 at J519), and via a thin wire from the busbar on the battery-top fuseholder via a 5A fuse designated S268, I think fitted in location 10 (though our manuals seem to suggest loc 11?) this terminates at XS4/pin 5 of J519.

 

Disconnecting the ground from the battery post, or removing that 5A fuse should make VCDS see a problem with the system voltage; if I'm right.  Will give it a go this evening, if no-one else can try it in the meantime. Could even feed in an independent voltage via the fuseholder (with a common 0V) to see if that voltage is what's read by J519 and thereafter by VCDS...if I'm feeling adventurous.

[rum4mo]

"Electric" PAS is actually a misnomer. Electro-hydraulic PAS would be better, since the electric part is an "on demand" motor supplying power to a hydraulic pump rather than the pump being directly driven from the engine accessory drive belt. Both systems still require a physical shaft between steering wheel and pinion (or steering box).

 

Read that again, I was referring to "electric" power steering as opposed to the electric-hydraulic systems in these small VAG cars of that age.

[KenONeill]

Read that again, I was referring to "electric" power steering as opposed to the electric-hydraulic systems in these small VAG cars of that age.

Seriously, I've never seen a system that uses the electric motor as anything more than a force multiplier.

[Breezy_Pete]

Self Study Programme 259 describes it all (electro-hydraulic PAS), I think. Available via erWin (VW, not sure about Skoda), or possibly other avenues.

I can confirm that the wires referred to in post #53 do seem to correlate well with VCDS seeing/not seeing battery voltage, so J519 really is giving an 'at battery' voltage in measuring block 2 of the central electrics controller. Taking out the 5A fuse in position 10 of the battery-top fusebox makes it go to zero, taking the (small) lead off the negative battery clamp actually makes it drop 25%-ish, rather than disappear completely.

My battery engine-off was at a worrying 12.1-12.2, but with engine on, a better 14.3V. This could only be persuaded to drop down to 13.8V by putting on dipped beam headlights, cabin fan on full blast and rear windscreen heater.
I cross-checked the first 12.2 reading with a multimeter right on the battery posts.

I do mostly short journeys, so I'm not too worried about the low battery voltage, but I'll be looking for a parasitic drain.

[KenONeill]

Self Study Programme 259 describes it all (electro-hydraulic PAS), I think. Available via erWin (VW, not sure about Skoda), or possibly other avenues.

I can confirm that the wires referred to in post #53 do seem to correlate well with VCDS seeing/not seeing battery voltage, so J519 really is giving an 'at battery' voltage in measuring block 2 of the central electrics controller. Taking out the 5A fuse in position 10 of the battery-top fusebox makes it go to zero, taking the (small) lead off the negative battery clamp actually makes it drop 25%-ish, rather than disappear completely.

My battery engine-off was at a worrying 12.1-12.2, but with engine on, a better 14.3V. This could only be persuaded to drop down to 13.8V by putting on dipped beam headlights, cabin fan on full blast and rear windscreen heater.

I cross-checked the first 12.2 reading with a multimeter right on the battery posts.

I do mostly short journeys, so I'm not too worried about the low battery voltage, but I'll be looking for a parasitic drain.

I can't see why you find the 12.2v engine off "worrying"; a lead-acid accumulator has a nominal 2.0v per cell, and 6*2.0 is 12.0. The "extra" 2.something engine running is the voltage that actually recharges the accumulator.

[Breezy_Pete]

Because nominal is just that (rounded off and approximate), not actual.  See the table in this link and you'll see that 12.2V is a lead-acid battery at only about 50% of full charge.

 

Many pretty traffic-light coloured tables exist with broadly the same info if you google-image  "car battery state of charge", but these usually aren't temperature-compensated like the excel spreadsheet linked above.

[KenONeill]

Because nominal is just that (rounded off and approximate), not actual.  See the table in this link and you'll see that 12.2V is a lead-acid battery at only about 50% of full charge.

 

Many pretty traffic-light coloured tables exist with broadly the same info if you google-image  "car battery state of charge", but these usually aren't temperature-compensated like the excel spreadsheet linked above.

If your Excel is correct, then HTF is an accumulator with that little charge in it actually starting your car?

[dm222]

Imagine that you have a bad connection to earth, could that burn a pump or ir would only make the pump not work while the connection is not fixed?

Also where is the connection from the pump to ground? Is that cable that connects the pump to the chassis?

 

And also what kind of error would that generate? "Short to Ground"?

Edited 27 July, 2015 by dm222

[Breezy_Pete]

If your Excel is correct, then HTF is an accumulator with that little charge in it actually starting your car?

50% of 60Ah (my Polo's battery capacity) is 30Ah. A (small petrol engine) starter motor takes about 100A ballpark, for what, 3 seconds? That's 100 x (3/3600) = less than 0.1 Ah. Piece of cake.

[fireballxl5]

 Right tested battery and alternator today and all tested out ok, car drove spot on this morning, until reaching the workshop that is, power steering cut off briefly as I dropped down into first to go through a large puddle on the track way.

 Before testing the battery and alternator, had a check of the wiring that runs from the A/C and alternator, in fact there were three lots of wiring going to block connectors that fitted onto a slider bracket, unplugged all three plugs to check for dirt ingress, one was a little grubby and the other two seemed clean, also discovered another earthing point on the n/s chassis, well hidden under the bulk of the wiring loom where it branches off, that comes out of a black boxed sleeve that runs along the chassis leg, if you look directly down over the back of the n/s headlamp, you can just see the earthing  point tucked between the loom sleeves with a 10ml nut. 

 These earths were checked and the nut was tightened up real tight, as when I first undid it, it seemed to be only nipped up and not compressed, one of the earth wires was of a heavy gauge and seemed to run directly to the pump or into the general direction of the pump.

 After this we tested the other components, battery voltage, charging, charging with the lights on, wipers on, heater on and the pass working, charging was good with no drops and fell within the required fields.

 Drove home later in the day and all seemed good, but only time will tell, oh yes the battery is a 60AH AKUMA.

[Breezy_Pete]

That 'only nipped up' earth sounds like a good candidate for having caused all of your PAS troubles. I'm pretty sure from your description that that's the main earth for the pump.

 

Fingers crossed you've sorted it.

[dm222]

 Right tested battery and alternator today and all tested out ok, car drove spot on this morning, until reaching the workshop that is, power steering cut off briefly as I dropped down into first to go through a large puddle on the track way.

 Before testing the battery and alternator, had a check of the wiring that runs from the A/C and alternator, in fact there were three lots of wiring going to block connectors that fitted onto a slider bracket, unplugged all three plugs to check for dirt ingress, one was a little grubby and the other two seemed clean, also discovered another earthing point on the n/s chassis, well hidden under the bulk of the wiring loom where it branches off, that comes out of a black boxed sleeve that runs along the chassis leg, if you look directly down over the back of the n/s headlamp, you can just see the earthing  point tucked between the loom sleeves with a 10ml nut. 

 These earths were checked and the nut was tightened up real tight, as when I first undid it, it seemed to be only nipped up and not compressed, one of the earth wires was of a heavy gauge and seemed to run directly to the pump or into the general direction of the pump.

 After this we tested the other components, battery voltage, charging, charging with the lights on, wipers on, heater on and the pass working, charging was good with no drops and fell within the required fields.

 Drove home later in the day and all seemed good, but only time will tell, oh yes the battery is a 60AH AKUMA.

 

Hope your problem is solved. Gees your talking about this, I don't think it connects to the pump directly but it's location seems to indicate that it's related to be pump? But it could also be radiator? Headlights?

 

Edited 27 July, 2015 by dm222

[dm222]

Update: defenity connected to the pump:

 

[fireballxl5]

Hope your problem is solved. Gees your talking about this, I don't think it connects to the pump directly but it's location seems to indicate that it's related to be pump? But it could also be radiator? Headlights?

 

Looking at yours it looks like a mk2, mines a mk1 facelift so the wiring could be different? Theres also a smaller gauge wire on the earthing point that also go's off in the general direction of the pump, but the only way to see whats really going on with mine is to take the bumper off.

[dm222]

Looking at yours it looks like a mk2, mines a mk1 facelift so the wiring could be different? Theres also a smaller gauge wire on the earthing point that also go's off in the general direction of the pump, but the only way to see whats really going on with mine is to take the bumper off.

 

This isn't my car, just an internet photo, but the mecanism is the same, look at the other photo I posted, there you can see clearly it connects to the pump...

[fireballxl5]

Update: defenity connected to the pump:

 

That looks pretty grubby and one of those pump plugs looks contaminated with oil and could be causing a short.

[dm222]

That looks pretty grubby and one of those pump plugs looks contaminated with oil and could be causing a short.

 

Not my car, just to show that the thing you said connects to the pump.

Also isn't the pump water resistant?

Edited 27 July, 2015 by dm222

[fireballxl5]

That looks pretty grubby and one of those pump plugs looks contaminated with oil and could be causing a short.

So what have you got a mk1 or mk2?

[dm222]

So what have you got a mk1 or mk2?

 

The car that is giving me problems isn't a skoda, it's an Ibiza... wich uses the same pump and the same design.

[fireballxl5]

The car that is giving me problems isn't a skoda, it's an Ibiza... wich uses the same pump and the same design.

OK, so at a guess yours will be earthed somewhere on the chassis in the general location of the pump, just follow the brown wire to the earthing point, undo the nut and remove the earth and clean the terminal end with sandpaper and refit, also check for oil contamination in and on the pump plugs, due to the stupid location of the filler cap to top up the PAS oil, often spillage can occur and more times than not, the oil will make its way down and around the pumps plug in terminals, oil in its self can cause short circuits if it gets into any of the pump plug in points

[dm222]

OK, so at a guess yours will be earthed somewhere on the chassis in the general location of the pump, just follow the brown wire to the earthing point, undo the nut and remove the earth and clean the terminal end with sandpaper and refit, also check for oil contamination in and on the pump plugs, due to the stupid location of the filler cap to top up the PAS oil, often spillage can occur and more times than not, the oil will make its way down and around the pumps plug in terminals, oil in its self can cause short circuits if it gets into any of the pump plug in points

 

My pump is new, I don't have problems right now, I had to replace twice, I'm just looking for the reason, I don't want to have to change the pump again. :(

Also when I wash the car the pump gets full of water, but I gess it must be prepared to it, isn't it?

[fireballxl5]

My pump is new, I don't have problems right now, I had to replace twice, I'm just looking for the reason, I don't want to have to change the pump again. :(

Also when I wash the car the pump gets full of water, but I gess it must be prepared to it, isn't it?

What do you mean, your pump gets full of water?

[dm222]

What do you mean, your pump gets full of water?

 

Water gets inside the capot and ends near the pump...

Edited 27 July, 2015 by dm222