No power steering or speedo and oil level warning

[DarkHorse]

I have a big problem with the car. I have oil sensor warning, power steering warning, no speedo. 

 

My mechanics tried to find the fault. Replaced G65, checked an earth point. Everything fine for 300 miles, then fuse blows again. They think it is something electrical but don't know what it is. 

 

I don't know what to do. No one knows what the problem is. And I need the car so I'm still driving, just getting tired arms. And I need to use a speed app from my phone. 

 

Has anyone had this problem before? Any solutions? 

 

Please help. 

[bret]

Which fuse blows? There was the story of the short in the engine bay from Skipton many moons ago... 

 

Have you had a scan recently?

 

 - Bret

[DarkHorse]

Fuse 38. I replaced it, two minutes later same faults again! 

 

I think I just read that one now. http://www.a2oc.net/forum/showthread.php?9095-Power-Steering-gone-again&p=69455#post69455

 

It was some kind of rubbing against the loom. Might see if that can be checked. 

 

Just can't believe it after spending so much money fixing everything else! 

[bret]

yep, the problems start now, though, because stuff like insulation is getting old and brittle.... 

 

 - Bret

[DarkHorse]

I will try to check if it is that problem. 

 

So it's not something that has really come up on the German forum then? Maybe the loom is routed differently on left hand drive cars so this has not been such an issue over there. 

 

Any other ideas please let me know. I'm at a loss and really want to keep the car. 

[bret]

no, it's not something that's been an issue here, at all. I'd start with disconnecting stuff and running around with a multimeter. I'm assuming WOM already checked the earth points on both sides at the base of the A-pillars.

 

 - Bret

[DarkHorse]

I'm not sure. I think they checked an earth point. It'll have to go back to them because I really don't have the technical know how to find the fault. 

 

My third child is 5mths and life is getting more and more hectic and expensive now with this problem!

 

I believe Tom (Timmus) also looked at it/gave advice briefly. I'm sure he could fix it. But in the meantime what should I do? Is it ok to drive with the warnings? I just have no speedo (using GPS speed app on phone) or power steering. 

[Peter_Maathuis]

I believe the G65 sensor is part of the airco and I do not understand why this sensor was replaced as it is not related to oil sensor, power steering and speedo. Or are these connected via fuse 38?

 

Is the fluid level in the power steering pump correct? If not, the power steering switches itself off. The level can be checked after removing the left headlight unit; using a flashlight makes it easier.

 

Also, if the speedo is not working, you might want to check if the radio (if it's original Audi) does display speed or not. Activate the "hidden" menu in the radio by pressing SCAN and preset 1 (if I remember correctly) simultaneously.

 

If the oil level (checked with the dipstick) is OK, I see no reason not to continue using the car.

Bearbeitet 8. März 2017 von Peter_Maathuis

[DarkHorse]

I believe g65 is part of the same circuit. But it was replaced because it had a fault. All levels were checked and the car drove about 300 miles before the fault came back. 

 

Previous owner kindly removed the original stereo 

 

Tomorrow I will get another fuse and make sure the ECON is on,then replace fuse. That way I can check to see if N280 or G65 is at fault. If the fuse doesn't blow then the problem is nearly located, if it does, back to square one! 

[Peter_Maathuis]

Another trick to check whether the speed signal is properly delivered to the instrument cluster is switching on the "anti-carjack autolock doors at 10 mph"-function. You (or your mechanic) need VCDS for that.

Do you have cruise control in your car and does it work? If not, the speed signal may be missing (I had that - turned out to be a faulty gateway in the instrument panel).

 

The speedo signal comes from the transmission and is distributed by the instrument panel) over the 3 CANbusses in the car. Also to the power steering, but I seem to remember that it uses intermediate assistance if it cannot provide speed-dependent assistance due to no speed signal.  The power steering uses quite some (electrical) power - a  low battery voltage and failing generator may also provoke a power steering switch off. You may want to check the voltage with the engine running.

[DarkHorse]

Thanks for the advice. I'll isolate the G65 and report findings. 

[DarkHorse]

Definitely not my G65. It is a brand new Audi part, replaced last week. Disconnected it this morning, replaced fuse, everything fine. Stationary full lock turn, and, you've guessed it, pop goes the fuse! I heard it. That's twice now, blowing at same moment this morning.

Doesn't narrow it down though, because it just means that the circuit is overloaded.

Maybe mine's the power steering pump too? I'll need to check the 80A fuse in the passenger footwell. Apparently water can get into the pump and cause problems.

[Peter_Maathuis]

This points to the power steering control unit, not the power steering pump itself (that draws way more than the 10A of fuse 38). I would disconnect (2 or 3 electrical connectors) the power steering unit completely and then replace the fuse.

 

I would expect your oil sender and speedo (and various other functions, see list) to work again.

 

Bearbeitet 9. März 2017 von Peter_Maathuis

[DarkHorse]

Thanks Peter, I'll get it checked.

 

Is it still possible that one of the other items on that list is causing the fuse to blow, and the power steering is simply pushing it over the edge because of the power it needs?

[Peter_Maathuis]

Though possible, it's unlikely as fuses typically have a large margin before they blow.

 

That is assuming you have switched off (where possible) the other "current users" in the list. Several items in the list will not even be installed in the car, but for example the radio could draw a few amps in loud passages... A control unit / regulator will not draw more than a few milliAmps when not in use.

 

You can easily find out whether it's marginal or a real short circuit by replacing the 10A fuse by 20A and do the power steering test again.

[bret]

agreed, that it's unlikely. I'd remove the aircon control panel, too, and see if that makes a difference.

 

 - Bret

[Romulus]

vor 1 Stunde schrieb Peter_Maathuis:

You can easily find out whether it's marginal or a real short circuit by replacing the 10A fuse by 20A and do the power steering test again.

Only for test purposes for a short while, of course! 

[DarkHorse]

Honestly, have to say a big thanks to all of you taking your time to advise me. It definitely requires some methodical electrical testing to isolate the fault. 

 

I'll report back with any significant developments.