Eighteen months ago, while in the dealership for other work, I was told that the ABC pump had failed. Apparently the car had sunk over a week or so and wouldn't lift up.

I had never had a suspension problem and it was fine when I drove it there.

They quoted $8000 for the pump and $1500 to install it.

I said I'd think about it and ordered one from parts.com for $1250.

When called the dealer to say that I would get my own pump for them to install they told me that the car had lifted itself up and everything was OK.

So, I have a brand new pump in an MB Box sitting on the shelf

Soon after I got the ABC Drive Carefully message and there was a puddle under the car after a 30 minute drive and the ABC reservoir was wet all around.

I cleaned it up, replaced the filter and did a flush using the lift switch to lift the car up and down.

Everything has been fine until the weekend when, after about 30 minutes of driving around the suburbs I got the ding and ABC Visit Workshop message. When I tried to lift the car with the button nothing happened except for the red death screen ABC Drive Carefully. I drove the 15 minutes home and tried lifting the car a few times with no result.

The car did not sink on the way home but the ride was a bit harsh over speed humps and wallowed at speed

After an hour in the garage I started it up and everything's fine: it lifts up and down no problems, no error messages

Fine yesterday for two 15 minute drives but did the same thing this morning after 20 minutes... ding and message and no lift. Fine when I returned 30 minutes later and on the 30 minute drive home.

When I got home there is a puddle where it usually sits and the ABC reservoir and all around it is wet.

I cleaned it all up and lifted the car up and down 20 times without problem.

Unfortunately my SDS does not talk to the ABC module so I can't check for codes.

It sounds like intermittent pump failure but in my mind a pump either works or it doesn't.

If it has failed and is providing low pressure through wear how can it then function perfectly and repeatedly lifting the car 20 times in quick succession?

The leak at the reservoir is a bit weird... it sounds as if too much fluid is being returned but the fluid level is at the right mark and I can't repeat the leak.

The car has 131,000km and it would be relatively straightforward to replace the pump but I'd like to know that it was definitely the problem before I went ahead and started replacing things like a dealer

I'd appreciate any advice

Thanks

 

It sounds like your ABC accumulator(s) have failed. Same thing happened to mine. When they fail, they can't absorb the shock from the road, and they cause hydraulic fluid pressure to spike through the system and it blows out the reservoir. It will lead to more damage if you don't fix them. They aren't expensive, and they are fairly easy to replace. Mine went out at 80k with the same symptoms you described.

 

Question to "cowiepeters": (Sorry for the problems you are having.)

When the suspension problem appears to be fixed, does the "ABC Drive Carefully" message clear itself or does the dealer have to reset this or do you have to take some special action to clear this? (I'm hoping that a new filter and flush will fix my ABC problems and clear the message.)

Thanks for your reply.

 

Thanks for the reply,

I suspect that the accumulators might be part of the problem but I am getting almost continual ABC visit workshop and drive carefully warnings which appear to be low pressure errors.

The car is booked to have the pump replaced and I'll follow up with the results

The above warnings clear when the ignition is switched off so they do not need to be reset by the dealer but I imagine that codes will be being stored.

 

Thanks for the info. Hope you get AOK without too much hassle.

 

I had the pump replaced last week. It took longer than expected due to a rusted bolt on the back of the pump that took several hours to remove.

On the delivery run it threw a white ABC fault and again on the way to work the next morning and it's been perfect since.

My new Star system allows me to access the ABC and I can read pump pressure and did a rodeo just to see. There was one low presure fault stored.

If I had the new system 2 weeks ago I would have been able to diagnose the problem sooner by measuring pump pressure.

All is well in the world again!