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Engine Management System Faulty -- No A/C

56K views 20 replies 7 participants last post by  pugthepug 
#1 · (Edited)
Car is a 2007 207 THP 150.

Second time this has happened. First time it happened was a couple of months ago, driving the car normally down the road, suddenly it beeps and says "Engine Management System Faulty" on the center console display. I then noticed that the A/C cooling function wouldn't work anymore.

The display in the dash would show the exclamation mark. Everything else in the car works perfectly EXCEPT cooling. Heating works. When I turn on the A/C I don't hear the compressor engage (the CLICK sound).

Then the following day I was running on fuel so I it beeped and I got another warning -- fuel low. The excalmation mark in the dash miraculously dissappeared, and the vehcile error log in the trip computer didn't show the engine management system fault anymore either. The A/C now works. Strange!

I wrote it off as 'gremlins' and went about my life. About 2 months later I get it again! So I break out my PP2000 and scan it. It says "Status of the Fan Assembly Coherence"; Fault code P0494.



I cleared the fault code, turned off the ignition as advised by PP2000 and back on, and now the A/C works! I can hear the compressor clicking on when I switch on the A/C.

Any idea on what this could be? A/C clutch? Compressor?
 
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#2 ·
Ok the a/c is still dead and the engine management fault is persistent. Reading error codes shows the same "Status of fan assembly coherence" error.

I've checked the fuses under the hood near the battery and also the ones in the glove box compartment near the diagnostics socket and I don't see anything amiss.

Can someone pls give some suggestions on where I can go from here to begin diagnosing? Perhaps tell me what a "fan assembly" is!
 
#3 ·
Hi,

I now believe that the issue is with the radiator fan. I was thrown a bit by the fact that the A/C didn't work, I thought the issue may be with the blower!

Using the PP2000 actuator test function I was able to run the radiator fan in both slow and fast modes, and also the intercooler fan so all fans are definitely working.

I will take a look at the radiator fan assembly/wiring tomorrow at daylight!
 
#4 · (Edited)
I have inspected the control unit at the fan and can't find anything obvious wrong with it or its connectors. Gave it a good blast with connector cleaner and wiped it down and put it back in and it didn't seem to help at all.

I believe Fan Control unit part 1267 J6 (shown in diagram below) is the culprit.



This part is worth quite a lot of money unfortunately. Would replacing it be the first thing to check? Anything else to look at first?
 
#5 ·
Ok I've fixed it -- I've taken out the sensor/part (part 1267 J6) again, and cleaned it with contact clean and gave it a really good wipedown, put it back in and started the car to find that the fault cleared itself. Drove the car over 400 km after that with the A/C running and there was no issue.
 
#7 ·
Unfortunately the fault is back now, and I've lost A/C cooling just like before. It happened on a clear, sunny day (and it hasn't rained here in about a week) so I think we can rule out moisture.

Here is the odd thing --- The second the fault triggered, I started watching the gauges very closely. Specifically, the coolant temperature gauge. I noticed that it was fluctuating between 70° C and 90° C. At one point, I saw it drop to 70 and go back up to 90 all in the space of about 30-45 seconds. Surely this is impossible?

I _WAS_ going to replace that sensor 1267 J6, but in light of this new data (coolant temp fluctuating so much) I'm starting to think, is there a chance something else (I'm looking at you, coolant sensor) is faulty?

What do you think?
 
#8 ·
It turned out to be a fautly fan relay. I took it out of the car again and smelt it, defintely smelt cooked. Obtained the wiring diagrams and broke out my multimeter and after some tests confirmed suspicions.

Then I took a great big hammer and smashed the other one to pieces. Yup, definitely looks like the magic smoke has escaped:







Note, After swapping the part out I still received the engine management system faulty error and no A/C, the error only went away once I held the engine at 3000 RPM for a while and coolant temp hit 97+ °c when the fan finally kicked in. Once the fan kicked in the triangle in the display dissappeared and the A/C began to work.
 
#11 ·
I am having the same as you had, Fan Assembly Coherence and also when I clear the system faulty by running the diagnostic the faulty stop showing, and after a while it returns. when I turn on my a/c it shows the green light on the button and it blows a bad smell out of the fans inside the car.

any help would be great full
my peugeot is 308 2009
 
#12 ·
I am having the same as you had, Fan Assembly Coherence and also when I clear the system faulty by running the diagnostic the faulty stop showing, and after a while it returns. when I turn on my a/c it shows the green light on the button and it blows a bad smell out of the fans inside the car.

any help would be great full
my peugeot is 308 2009
 
#15 ·
See attachment. It has a diagram of your radiator pack.

If you have PP2000, try to activate the fan manually from the diagnostics and see if it works. If not, you know what the problem is.

If it works, then take out part #6 and test it with a multimeter. (I've attached a wiring diagram too).

I was able to tell mine was faulty by just smelling it, it smelt burnt, but the fan speed control diagnostic test in PP2000 was working perfectly



 

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#16 ·
Hi, saw this post, wife's 207cc had same problem,( A/C not working and warning triangle on screen , with some management fault message).:(. So following suggestions on here decided to remove rad fan relay/sensor to check resistances etc, while it was off cleaned up terminals, then after taking numbers off unit to obtain another unit , refiited it,(so didn't lose it while waiting to get new one),started car up, no warning on screen:eek:, so tried A/C , heard familar clunk and wahay:eek: A/C started, tried it several times, still worked, been 3 - 4 weeks, still working, no messages.. So to all who contributed on this thread; A VERY BIG BIG THANK YOU,, who knows what it would've cost to have diagnosed/repaired at a dealers..
 
#17 ·
I have zero experience in auto electronics, but have experience in general diagnostics and electronics on a hobby level, and I am genuinely surprised at how easy these faults are to diagnose.

The fact that people are dreading taking their cars to the workshop due to such incompetence is quite frankly shocking.
 
#18 ·
Had the "Engine Management System Faulty" error popped up in my 308 center display. Had similar symptoms as explained by bung206. My temperature gauge went back&forth between 80 to 90 degrees. However when it first occurred, it went all the way up to almost reaching the redline.

Will send to service center soon as I don't have the PPS to diagnose. But will keep in mind about the faulty fan relay.

Thank you for sharing this. It helps a lot.

Regards,
Faisto, Malaysia
 
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