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W168 A160 Intermittent Power Steering Failure (When idling?)

11K views 4 replies 2 participants last post by  Greenspoon 
#1 ·
Hi wonderful people. Long time reader, first time poster.

My cherished 2001 A160 Semi auto has been a bit naughty lately. On three occasions over the last 10 days, when reverse / parallel parking, the power steering has gone off.

All three times the car was being reverse parked, and so I imagine the wheel was at full lock, or nearly, and the car was idling, or close to it.

On each occasion, the engine was switched off, then back on again and it was fine.

Today, when my wife was driving, she had the A/C on (I never do) and it went off three times while reverse / parallel parking (I think because it took her three goes to reverse).

I have no idea what is going on - please any help with what it might be, or how I can diagnose?

From my searches I'm guessing alternator, power steering pump or battery?

We have already had the ECU replaced at close to $3000, I don't think I can afford another big problem. I just wish I didn't love the LWB design of the car so much!



Thanks heaps!
 
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#2 ·
It definitely sounds like an alternator/charge related problem: the power steering electric pump is triggered by a small blue wire which enables it only after the engine has started and the alternator is feeding enough current to the battery not to discharge it. If your alternator is faulty or the belt slips, there can be a drop in voltage (and current) leading to the temporary disabling of the power steering pump. I suggest you have your alternator checked (you can use a voltmeter and turn on all lights plus defrost and A/C, the voltage across the battery should stay at 13.8). Alternatively there may be a loose wire in the pump housing or other side towards alternator causing the voltage to drop randomly.
 
#3 ·
Thanks so much for the reply. We were going to get the battery changed, as I think it's still the original battery sitting in there, so I'm hoping that is a potential solution. When I'm there hopefully they won't mind doing the alternator test you described (I don't have a voltmeter)!
 
#4 ·
For the sake of anyone else with the same problem - good news!
After the problem persisted and became evident every time we parked, we took the battery to get thoroughly tested and one of the cells had died. Put a new battery in and haven't had the problem for three days. Seems to be fixed! Thank goodness it was the cheapest repair option possible.

So for anyone with power steering intermittent failures in future, test your battery!
 
#5 ·
Update

So, the problem came back quickly enough. We had it diagnosed as the power steering pump. Dealer quoted $3000 for the part alone. ROBBERY!

However we did find a used pump from a wrecker for just $250. Phew... Steering is totally perfect now, fingers crossed it stays that way!
 
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