P38 stuck in access mode - no fault shown

jeffers · Apr 7, 2013

Datatek- yep thanks for the correction. The results the same though unfortunately, the 2 ohms is just my crap meter it is a proper earth. The odd thing is that the compressor appears to be starting and stopping randomly. Like it comes on for about a minute then goes off for 5 minutes then on for 30 seconds off for 30 seconds back on for a couple of minutes and off again for ages. All this without changing heights or anything and the pressure switch is still showing open circuit so not up to pressure. Have left it on high height with the relay out tonight to check for any leaks.

wammers · Apr 7, 2013

jeffers said:
As said above - I have used the eas unlocker to get her up and I have pulled the relay. Unless I'm not understanding things correctly the fact that the compressor will run at will by using the eas software means the thermal fuse is fine and also the compressor whilst not pristine is giving enough pressure to both get to "high" and to cut off via the pressure switch when I did have it running yesterday. The problem seems to be that the ecu is not telling relay 20 to start the compressor correctly. With everything connected and the engine running, if I pull the delay relay and plug it back in the compressor starts and then stops after about 30 seconds now, yesterday it was working fine. I have even pulled connection 6 and drained the air receiver and still the compressor doesn't run for more than 30 seconds unless forced manually and then I get up to about 110psi in about 12 mins. Still stumped I will however put her on high and see if there is any drop in the morning.

Just resorted to looking at Rave and I see that my assumption about the thermal fuse is not correct. The compressor can be forced on even with the thermal fuse gone. Checked the thermal fuse and there is a 2 ohm resistance between the orange and black wires on the compressor plug which seems to be correct. So still no joy

The compressor can be forced to run either by bridging the relay or with diagnostics. That DOES NOT mean the thermal switch is fine. Read the "HOW TO" and do the checks. That is what it is there for, so people don't have to go through long drawn out diatribe about the same faults two or three times a week.

jeffers · Apr 7, 2013

Wammers - agreed and found that out now. Perhaps it would be worth including in the "How to" that the compressor can be made to run even if the thermal switch is faulty. It is in fact a seperate circuit that is an input to the ecu. Anyway my thermal switch appears to be OK and I'm still not any closer to finding my problem. I'm still unsure of what part of the "How to" that you think I haven't followed?

wammers · Apr 7, 2013

jeffers said:
Wammers - agreed and found that out now. Perhaps it would be worth including in the "How to" that the compressor can be made to run even if the thermal switch is faulty. It is in fact a seperate circuit that is an input to the ecu. Anyway my thermal switch appears to be OK and I'm still not any closer to finding my problem. I'm still unsure of what part of the "How to" that you think I haven't followed?

Your compressor is knackered if it takes 12 minutes to give 110 psi. Maybe the thermal switch is tripping to soon or the compressor is getting hot very quickly. Get the compressor right first of all. Have you done the diaphragm valve check?

jeffers · Apr 7, 2013

wammers said:
Your compressor is knackered if it takes 12 minutes to give 110 psi. Maybe the thermal switch is tripping to soon or the compressor is getting hot very quickly. Get the compressor right first of all. Have you done the diaphragm valve check?

I will bite the bullet and order a new pump. As you say, lets get one thing right first. I have done the diaphragm check. Thanks again for your help.

jeffers · Dec 9, 2013

I ended up changing the compressor and all was fine afterwards.

P38 stuck in access mode - no fault shown

jeffers

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wammers

No longer with us, RIP

jeffers

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wammers

No longer with us, RIP

jeffers

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jeffers

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