So a while ago I declared on here I was done with daily driver wrenching having lost the passion and time being short. Just taken my daughters 07 P2 Chassis V60 in for some work Inc, T.belt, idlers, H20 Pump, rear shocks, tie rod end, alignment and a couple of things to diagnose. I've now got a couple of Q's for the cognoscenti.
- When left for a few hours or overnight the brake vacuum will drain down, meaning you either need to sit for 30 seconds on start up, or you have a rock hard pedal with no vacuum at first. I couldn't find an issue, but thought it would be a no brainer for the garage with a vacuum leak smoke detector kit. They can't find a problem. Any known hard to find gotchas on these cars vacuum system?
- The car has a traction control wheel sensor issue according to the dash info, which I assumed would also prevent the ABS from working. But I now need to confirm that as they say when they went to diagnose they are getting a message that the steering angle sensor is faulty, and that would another $764 to R&R, well I'm into this for well over $2k now so told them not to bother with the steering angle sensor for now, so I'm wondering where it is and how hard it is to replace. Is it in the steering wheel hub, as I need to get a new left hand column stork as the high beam function has failed so I'll be pulling off the steering wheel soon anyway.
TIA
Volvo likes to use a lot of check valves in its vacuum systems, I would guess you have a bum check valve in the booster circuit if the system isn't leaking to atmosphere.
I'm not familiar with the P2 steering angle sensor setup specifically but many I've seen on other cars are incorporated into the airbag clock spring assembly on the column.
pointofdeparture said:
Volvo likes to use a lot of check valves in its vacuum systems, I would guess you have a bum check valve in the booster circuit if the system isn't leaking to atmosphere.
I'm not familiar with the P2 steering angle sensor setup specifically but many I've seen on other cars are incorporated into the airbag clock spring assembly on the column.
thx. Do you have a vacuum diagram as they said the check valve was good. Maybe there's more than one?
In reply to pointofdeparture :
Mention of possible problem with the clockspring and above he mentions problem with the "brights" switch. I wonder if this brights switch runs through the clockspring wiring too? That might point to no problem with the brights switch but just problem with the clockspring.
In reply to Adrian_Thompson (Forum Supporter) :
My P80s all had 3-4 check valves in the system. I could try to track down a diagram for you but would need to know the trim level and engine in the car.
In reply to John Welsh :
The stalk is normally upstream of the clock spring, I would not think the problems are related unless there is something further up that would affect them both (bad connection at column harness, etc).
Also, they could just be blowing into the check valve which might indicate that it hasn't totally failed, but might not hold a vacuum for 8+ hours. Normally they are like a $6 part, cheap enough to just replace for peace of mind.
There should be a brake pedal position sensor in the engine bay face of the brake booster, near the master cylinder. It has an O ring that likes to leak. Easy repair.
If it takes that long to build brake assist, though, it sounds like the vacuum pump is dead, or it isn't being commanded on. It is somewhat normal for brake boosters to bleed down, and the turbo Volvo engines build no vacuum on a cold start due to engine management concerns, so there is a vacuum pump in the system. It's the same generic Bosch unit that everyone else uses.
my S60 builds brake assist key on engine off, and you can hear the pump working, when the engine is not running.
If you were closer, I'd throw my scantool on it and have a look.
