RR Valve Stuck Compressor runs Constantly

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jimllshiftit

jimllshiftit

Active Member
Posts
235
Location
Warwickshire
Hello again all,

P38 EAS went into shock again yesterday. I wasnt in it at the time but im told it did its little dance routine in a car park and then went into 35 max mode.

I've cleared the fault which said RR Valve Stuck Open. The suspension then inflated on three corners but not the RR so I went through all the levels a few times to and then got all four corners inflated.

During this I noticed that the compressor ran for, say, 10 secs then stopped for 5 secs then 10 secs again and so on but when I'd got all the bags inflated the compressor started running constantly.

Is it the valve thats causing the problem or is it the valve being kept open by something else? What have I got to do to repair this?
 
jimllshiftit said:
Hello again all,

P38 EAS went into shock again yesterday. I wasnt in it at the time but im told it did its little dance routine in a car park and then went into 35 max mode.

I've cleared the fault which said RR Valve Stuck Open. The suspension then inflated on three corners but not the RR so I went through all the levels a few times to and then got all four corners inflated.

During this I noticed that the compressor ran for, say, 10 secs then stopped for 5 secs then 10 secs again and so on but when I'd got all the bags inflated the compressor started running constantly.

Is it the valve thats causing the problem or is it the valve being kept open by something else? What have I got to do to repair this?
Click to expand...

The valve stuck open/closed fault is often not the valve at all.The eas ecu expects a certain parameter to be reached in a set time and when it isnt it throws up a faullt like this.In this case it may have been waiting for the RR to rise and when it didnt, it threw up the fault.

Take out the EAS timer under the passenger seat overnight and if the RR is on the bump stops in the morning you have a leak there.
 
I had a funny feeling that replacing the valve wouldnt be the first port of call - 6 months p38 ownership has taught me that much at least.

Ill get the timer out now and see what happens.
 
Went to the car this morning to find that all four corners are still inflated after removing the EAS Timer last night. Just to check, the timer is that 3x1x1 inch black box thats the first thing you come to after taking the seat base surround off?

If its not a leak then what is it. Ive been getting the Pressure Signal High reading about once a month so is this current problem being caused by a faulty driver or something else altogether?
 
jimllshiftit said:
Went to the car this morning to find that all four corners are still inflated after removing the EAS Timer last night. Just to check, the timer is that 3x1x1 inch black box thats the first thing you come to after taking the seat base surround off?

If its not a leak then what is it. Ive been getting the Pressure Signal High reading about once a month so is this current problem being caused by a faulty driver or something else altogether?
Click to expand...

The driver pack has no connection to the compressor circuit. Other than activating the diaphragm solenoid valve when compressor is running. It simple does not run the compressor. It maybe however a faulty driver pack opening a valve and constantly exhausting a bag then filling it. Check pressure switch is functioning first of all.
 
Thanks Wammers - for clarity can we just confirm that to do that I need to put a multimetre across pins 7 and 9 of c141 connector. From rest there should be some resistance but after running the compressor for a while there should be no resitance. What setting does the multimetre need to be on?

Forgive me if that sounds silly but Im the first to admit that I still have a great deal to learn.
 
jimllshiftit said:
Thanks Wammers - for clarity can we just confirm that to do that I need to put a multimetre across pins 7 and 9 of c141 connector. From rest there should be some resistance but after running the compressor for a while there should be no resitance. What setting does the multimetre need to be on?

Forgive me if that sounds silly but Im the first to admit that I still have a great deal to learn.
Click to expand...

Don't know where you got connector C141 from. Switch wires go to pins 7 and 9 of connector C0871. There should be full continuity (No resistance closed circuit) across switch wires at 140 psi with compressor off.
 
Last edited:
Looking at the ETM for the 1997 MY....

C141 is the Big multiplug on the Valve Pack....

As Attached.....
 

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  • P38_C141.jpg
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Saint.V8 said:
Looking at the ETM for the 1997 MY....

C141 is the Big multiplug on the Valve Pack....

As Attached.....
Click to expand...

It is not listed on the electrical manuals i have. The loom socket that plugs into it C0871. Anyway, as far as i understand it. Switch has a falling resistance as pressure builds and a raising resistance as pressure drops. It is not just an on/off switch as some would think. The OP may want to look at the compressor relay if it is always running.
 
Last edited:
Whatever the connector's called I think we are all talking about the same thing. I got c141 from the RSW pressure sensor check video on youtube but also found that picture of c0871 after wammers' last post.

Anyway, Ive got resistance with the pump at rest and continuity after the pump has run for 5-10 minutes. But - everything has gone back to normal. When changing heights the pump now runs as it should, for a minute or two and then stops until you want to go up a level. It definately wasnt doing that this morning.

What should I do now?
 
jimllshiftit said:
Whatever the connector's called I think we are all talking about the same thing. I got c141 from the RSW pressure sensor check video on youtube but also found that picture of c0871 after wammers' last post.

Anyway, Ive got resistance with the pump at rest and continuity after the pump has run for 5-10 minutes. But - everything has gone back to normal. When changing heights the pump now runs as it should, for a minute or two and then stops until you want to go up a level. It definately wasnt doing that this morning.

What should I do now?
Click to expand...

Check the compressor relay. It maybe sticking closed intermittently.
 
I dont know how to do that without looking it up so ive just pinched the compressor relay out of my spares heap and stuck that in for the time being. Fingers crossed!
 
jimllshiftit said:
I dont know how to do that without looking it up so ive just pinched the compressor relay out of my spares heap and stuck that in for the time being. Fingers crossed!
Click to expand...

When relays get worn sometimes the return spring gets weak and the contacts burn over time. It only takes a spark to weld the contacts together. You have changed it see how it goes.:):)
 
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