P38A EAS Fault, how to pin-point

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Henrik97

Active Member
Posts
301
Hi all,
Car is a '97 4.6 HSE.
Over the last few months, it has thrown up an EAS fault on approximately every 3 or 4 drives. I thought maybe my compressor was going weak, so I have just replaced the cylinder and piston seal, but that didn't help much. It does pressurise quicker and raises instantly every morning, but it still goes into fault mode every now and again. I use the EAS kicker to reset and she returns to normal every time, but it still bugs the hell out of me and I'd wish to find the fault and fix it. Any suggestions?
FYI, all four airbags have been replaced over the past two years, so they should be good. I did the valve block about 3 years ago.
I'm suspecting a height sensor on the way out, but how to tell? Does the cable and software kit from Datatek let me run my own diagnosis? Can it be used to calibrate a replacement height sensor, if that turns out to be the problem?

Thanks!
Henrik
 
Henrik97 said:
Hi all,
Car is a '97 4.6 HSE.
Over the last few months, it has thrown up an EAS fault on approximately every 3 or 4 drives. I thought maybe my compressor was going weak, so I have just replaced the cylinder and piston seal, but that didn't help much. It does pressurise quicker and raises instantly every morning, but it still goes into fault mode every now and again. I use the EAS kicker to reset and she returns to normal every time, but it still bugs the hell out of me and I'd wish to find the fault and fix it. Any suggestions?
FYI, all four airbags have been replaced over the past two years, so they should be good. I did the valve block about 3 years ago.
I'm suspecting a height sensor on the way out, but how to tell? Does the cable and software kit from Datatek let me run my own diagnosis? Can it be used to calibrate a replacement height sensor, if that turns out to be the problem?

Thanks!
Henrik
Click to expand...

Sensor maybe, although damp on the white plug connections behind trim passenger side footwell at base of L/H A post can cause this. Drivers side if it's a left legger. It is the interface from the height selector button to the ECU. Cable and software from Keith will do all you need on EAS. You will need a laptop to run it.
 
Diagnostics will probably reveal a dud height sensor ... when you try to adjust a height the dud one won't respond properly. Storey Wilson's software will allow you to do this.
Does this happen when in Highway mode? (which is likely where most of the wear on the sensor track occurs).

Alternatively, remove the sensors in pairs and try operating the arms with an Ohmmeter attached and look for dead spots.

It might then be possible to swap them from side to side. By doing this, a fresh part of the sensor track is used.
 
Thanks both of you.
Wammers: That connector in the footwell is non-existent. I removed it a couple of years back and soldered each individual connection and covered with shrink tube.
Spiggy: Swapping the sensors seems like a clever idea. Can I remove them without having to re-sync the system?
I think I'll PM Data and get a hold of the cable and software, it's probably better than searching around without knowing where to look.
The fault occurs in regular mode, not highway, although I'm not sure that's true for every time it's happened. However, since I'm in Norway, where road speed is relatively slow by European standards, this car has spent most of its life at normal height.

Thanks again,
Henrik
 
Henrik97 said:
Thanks both of you.
Wammers: That connector in the footwell is non-existent. I removed it a couple of years back and soldered each individual connection and covered with shrink tube.
Spiggy: Swapping the sensors seems like a clever idea. Can I remove them without having to re-sync the system?
I think I'll PM Data and get a hold of the cable and software, it's probably better than searching around without knowing where to look.
The fault occurs in regular mode, not highway, although I'm not sure that's true for every time it's happened. However, since I'm in Norway, where road speed is relatively slow by European standards, this car has spent most of its life at normal height.

Thanks again,
Henrik
Click to expand...

If you swap the sensors, providing they are the newer ones that is possible. You may have to re-calibrate the heights.
 
Check driver pack connections. The sockets in C139-C140 between driver & valve block can cause random faults.

Discovered mine after doing 20mile Nanocom EAS Log, and then analysing the data using MS Excel. Logs were showing mismatched height changes versus valve opening/closing, with EAS randomly going into soft-fault every few days. Squeezed the contacts slightly, and never had the same issue since.

Pete
 
pwood999 said:
Check driver pack connections. The sockets in C139-C140 between driver & valve block can cause random faults.

Discovered mine after doing 20mile Nanocom EAS Log, and then analysing the data using MS Excel. Logs were showing mismatched height changes versus valve opening/closing, with EAS randomly going into soft-fault every few days. Squeezed the contacts slightly, and never had the same issue since.

Pete
Click to expand...
Thanks Pete, I will have a look. It sounds plausible, as the EAS functions faultlessly most of the time. When it plays up, it usually starts with all the level lights lighting up, sometimes flashing, other times just constant, before the beeper goes off and I get the fault message in the display. Sometimes, after I've used the kicker, it needs a couple of minutes at idle and then suddenly rises as it should.

Henrik
 
Henrik97 said:
Thanks Pete, I will have a look. It sounds plausible, as the EAS functions faultlessly most of the time. When it plays up, it usually starts with all the level lights lighting up, sometimes flashing, other times just constant, before the beeper goes off and I get the fault message in the display. Sometimes, after I've used the kicker, it needs a couple of minutes at idle and then suddenly rises as it should.

Henrik
Click to expand...

Have a look at connectors in valve block plugs. Firm them up see what you get.
 
Pete, Wammers,
I had a quick look. It seems I have to remove the valve block to get at C139 / C140. Fine. But is it a similar connector to the more accessible one, C152 at the front right of the pump? I ask because this connector, at least, is quite sealed so I don't see how I would get at the individual connectors to pinch them tighter. I appreciate your advice.

Thanks!
Henrik
 
I did mine on the bench. While refurbishing the valve block, you can disconnect the two pins going to the pressure switch. Then use one of these pins to check the fit into the valve block sockets.

If they are loose, you can remove the sockets one at a time to squeeze them (gently). To remove the sockets or pins, slide a jewellers screwdriver into the back of the housing and release the clip.

It is also possible to squeeze the sockets from the front using fine long nose pliers, but you will need electrical small pliers, not mechanics pliers !!

Pete
 
Henrik97 said:
Pete, Wammers,
I had a quick look. It seems I have to remove the valve block to get at C139 / C140. Fine. But is it a similar connector to the more accessible one, C152 at the front right of the pump? I ask because this connector, at least, is quite sealed so I don't see how I would get at the individual connectors to pinch them tighter. I appreciate your advice.

Thanks!
Henrik
Click to expand...

The inner cover of the socket can be removed (carefully) this gives you access to the pin holders they can be released with a small screw driver. Take them out one at a time firm up and replace. Then click internal cover back in.
 
Hi guys,
Finally, I believe I've cracked it. I did everything on the list:
- Eliminated both white connectors behind kick panel by clipping and soldering each wire
- Rebuilt compressor (again)
- Rebuilt valve block (again)
- Went over the entire circuit with leak detector (tiny leak found on one rear bag connector - sorted)
- Cleaned and firmed up both multi-pin connectors in EAS-box
None of the above did the trick though. I tried the cable and software from Keith, but was unable to read the faults. I then went and purchased a new USB-to-R232 converter locally, instead of the $2 P.O.S. I got off ebay and hey presto! Now it works! I have plugged in every time I've had a fault over the last couple of weeks, and each time there have been two: "Vehicle has moved" and "pressure signal constantly high". I did a search, and found that replacing the driver pack has worked for most, if not all, having the same problem, so now a new one is on order :)
Once I've solved this issue I will regrettably put the old girl up for sale, but all is not dark - her place will be taken by a 2007 Vogue TDV8 which I'm picking up on wednesday :D. The P38 is a fine car and great value, and she's served me well, but this is in a new league entirely - what a machine! Can't wait;)

Henrik
 
Henrik97 said:
Hi guys,
Finally, I believe I've cracked it. I did everything on the list:
- Eliminated both white connectors behind kick panel by clipping and soldering each wire
- Rebuilt compressor (again)
- Rebuilt valve block (again)
- Went over the entire circuit with leak detector (tiny leak found on one rear bag connector - sorted)
- Cleaned and firmed up both multi-pin connectors in EAS-box
None of the above did the trick though. I tried the cable and software from Keith, but was unable to read the faults. I then went and purchased a new USB-to-R232 converter locally, instead of the $2 P.O.S. I got off ebay and hey presto! Now it works! I have plugged in every time I've had a fault over the last couple of weeks, and each time there have been two: "Vehicle has moved" and "pressure signal constantly high". I did a search, and found that replacing the driver pack has worked for most, if not all, having the same problem, so now a new one is on order :)
Once I've solved this issue I will regrettably put the old girl up for sale, but all is not dark - her place will be taken by a 2007 Vogue TDV8 which I'm picking up on wednesday :D. The P38 is a fine car and great value, and she's served me well, but this is in a new league entirely - what a machine! Can't wait;)

Henrik
Click to expand...

Vehicle has moved is not a fault it simply means a sensor reading has changed since the last use. By self leveling for instance. Pressure signal constantly high is another matter. Whilst the driver pack has nothing at all to do with pressure circuit and controls it in no way. It does appear that a faulty driver pack can cause electrical noise feedback into the ECU causing this fault to be thrown. But this can also be down to bad connections.
 
Last edited:
Henrik97 said:
Once I've solved this issue I will regrettably put the old girl up for sale, but all is not dark - her place will be taken by a 2007 Vogue TDV8 which I'm picking up on wednesday :D. The P38 is a fine car and great value, and she's served me well, but this is in a new league entirely - what a machine! Can't wait;)
Henrik
Click to expand...

Reckon we'll be seeing a lot more of you then. :) ;)
 
tomcat59alan said:
Oh yes, a great deal more of you.;) and it's going to cost you more.
Click to expand...

Maybe so, although I doubt that the support for the newer models is as useful and comprehensive as that for the P38... Anyways, it's a low-mileage example with everything working, so I hope it will last a few weeks before I need to get the spanners out;).

FWIW: The new driver pack has sorted my EAS. No beeps and quick to react on the button. Finally! - it's been driving me nuts for ages now.
 
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