Another AC Gremlins thread

RoryK · #1 08-05-2018, 11:36 AM

Hi All,

I recently bought a 2003 3.0i e53 X5 with only 64k miles on the clock, one elderly gentleman owner and plenty of BMW Sytner history, but there is a few jobs I need to sort on it to get it back to former glory.

The main problem I have at the moment is the AC, I will start from the beginning and go through what I have done so far:

Problem: AC Blowing hot / warm air at all times.

I have done the basics of disconnecting the battery, checking the fuses and clearing down the ecu of any errors etc to no avail.
First point of all was to have the car re-gassed by my local dealer, system check and no leaks and the correct pressure levels applied - No Fix
Inspection of the Compressor confirmed the clutch was not engaging when turning on the AC, plugged in my INPA diagnostics software and as seen, an error code under AC confirming the coil was faulty.
Fast forward 2 weeks and a replacement coil arrives from Germany, I whipped the compressor off the car, replaced the coil and the clutch starts to engage and work as expected, Great! Check my diagnostics software, clear the code and it no longer returns, Perfect! so I take it down to the local dealer to get it re-gassed feeling like a job well done, and 1 hour later I get a call 'Your system has been gassed and it has no leaks, but you are not getting any cold air'
So I bring the car home and then spend the evening troubleshooting and googling my way through various topics to no real drawn conclusion.
So this is where I start scratching my head a little, the AUX fan, or the pusher fan.. whatever you want to call it doesn't turn on when when you turn on the AC, from what I have read, and through experience with other cars this fan should kick in as soon as I turn on the AC.
I have tested the connector and the fan is receiving a 12v feed just fine, the small black line I am assuming is some kind of signal wire that sends a pulse from the ecu, as I couldn't trace the line back to a a relay box and I do not have an oscilloscope to hand to check the signal from this wire.
There are 100's of posts that would lead me to believe the AUX fan has failed, but I found if I unplug the AC pressure switch, the AUX fan suddenly springs to life and spins up to full speed, but I cannot force it to work on any of its 3 stages via my diagnostics software <--- my First curious ????

With the above in mind, this would suggest that there is a fault with the signal going to the fan.. so now I just need to find out where that bad signal is coming from or why? and for this reason I am reluctant to spend the £££ on a new fan, as I am not entirely convinced it is the issue.

What I have done is ordered a new lower pressure switch, in the thinking that this is not sending the correct pressure reading, in turn stopping the ecu from engaging the AC system correctly as a safety precaution.

But whilst I wait for the new pressure sensor to arrive, does anyone else have any ideas or experience that could point me in other directions? or is there anything I have missed? I have checked out the diagrams on realoem.com and the system is pretty simple so it is a process of elimination I guess, working with the cheapest fix first.

Thank you in advance for your time!

Cheers

Sponsored Links

upallnight · #2 08-05-2018, 12:34 PM

Since you have INPA, you can scan the DME module and see if it list a fan fault. Testing of the Aux Fan is done by the DME. If the fan fails the test, the fault will be listed in the DME module. The test is for the DME to power on the fan at the beginning when the engine is first started, the start signal is removed so now the fan is freewheeling without any power to it. If you remember the properties of a DC motor it can become a generator if the armature is spinning in the field coil. The DME will look for a voltage signal from the signal wire to determine if the fan is spinning.

RoryK · #3 08-05-2018, 01:40 PM

Just did a scan and got nothing back, also just noticed the clutch wont engage again when switching AC on or off.... clutch works if I send the signals from INPA though.. Think I am going to sleep on it.. maybe the compressor is knackered.. it is a Calsonic Kensi after all...

upallnight · #4 08-05-2018, 09:16 PM

Quote:

Originally Posted by RoryK

Hi All,

I recently bought a 2003 3.0i e53 X5 with only 64k miles on the clock, one elderly gentleman owner and plenty of BMW Sytner history, but there is a few jobs I need to sort on it to get it back to former glory.

The main problem I have at the moment is the AC, I will start from the beginning and go through what I have done so far:

Problem: AC Blowing hot / warm air at all times.

I have done the basics of disconnecting the battery, checking the fuses and clearing down the ecu of any errors etc to no avail.
First point of all was to have the car re-gassed by my local dealer, system check and no leaks and the correct pressure levels applied - No Fix
Inspection of the Compressor confirmed the clutch was not engaging when turning on the AC, plugged in my INPA diagnostics software and as seen, an error code under AC confirming the coil was faulty.
Fast forward 2 weeks and a replacement coil arrives from Germany, I whipped the compressor off the car, replaced the coil and the clutch starts to engage and work as expected, Great! Check my diagnostics software, clear the code and it no longer returns, Perfect! so I take it down to the local dealer to get it re-gassed feeling like a job well done, and 1 hour later I get a call 'Your system has been gassed and it has no leaks, but you are not getting any cold air'
So I bring the car home and then spend the evening troubleshooting and googling my way through various topics to no real drawn conclusion.
So this is where I start scratching my head a little, the AUX fan, or the pusher fan.. whatever you want to call it doesn't turn on when when you turn on the AC, from what I have read, and through experience with other cars this fan should kick in as soon as I turn on the AC.
I have tested the connector and the fan is receiving a 12v feed just fine, the small black line I am assuming is some kind of signal wire that sends a pulse from the ecu, as I couldn't trace the line back to a a relay box and I do not have an oscilloscope to hand to check the signal from this wire.
There are 100's of posts that would lead me to believe the AUX fan has failed, but I found if I unplug the AC pressure switch, the AUX fan suddenly springs to life and spins up to full speed, but I cannot force it to work on any of its 3 stages via my diagnostics software <--- my First curious ????

With the above in mind, this would suggest that there is a fault with the signal going to the fan.. so now I just need to find out where that bad signal is coming from? and for this reason I am reluctant to spend the £££ on a new fan, as I am not entirely convinced it is the issue.

What I have done is ordered a new lower pressure switch, in the thinking that this is not sending the correct pressure reading, in turn stopping the ecu from engaging the AC system correctly as a safety precaution.

But whilst I wait for the new pressure sensor to arrive, does anyone else have any ideas or experience that could point me in other directions? or is there anything I have missed? I have checked out the diagrams on realoem.com and the system is pretty simple so it is a process of elimination I guess, working with the cheapest fix first.

Thank you in advance for your time!

Cheers

I would like to know how did they regas the system if the compressor wasn't engaging? If the compressor was engaged and they were able to regas the system, then most likely if you have a variable displacement then the vane is stuck in the lowest displacement setting and the compressor is not able to produce the high side pressure necessary for the system to work properly. Did they have a set of manifold gauges connected to both the low side and high side of the system? What were the readings?

RoryK · #5 08-06-2018, 05:04 AM

The clutch was engaging when they were applying the gas, It was my fault it stopped working after

In my tiredness and spending the whole day in the hot weather in a black car with black leather and no aircon I found myself running out of steam and making silly mistakes, in INPA I noticed a new error under the AC, which was 'error 52: Energy saving mode', scratched my head for a while and realised that transport mode was enabled, disabled transport mode and the error cleared leaving no error codes under the AC and also the clutch now engages and disengages when controlling from the AC interface in the car, or in INPA.

I think what you just said though @upallnight confirms my suspicion, in that the compressor is done and needs replacing, Come to think of it the low lines were not even cold when running on max, and also when I was looking at the gauges in the garage after it had been filled, the PSI wasn't fluctuating with the AC on max which I would expect it to, I cannot remember the figures but if memory serves me correctly the low pressure should move between 25 to 40ish depending on the cycle....?

I have cancelled the order for the low pressure sensor, and ordered a new compressor instead with the hope I can put this one to bed and move onto the next job!

upallnight · #6 08-06-2018, 08:50 AM

Quote:

Originally Posted by RoryK

The clutch was engaging when they were applying the gas, It was my fault it stopped working after

In my tiredness and spending the whole day in the hot weather in a black car with black leather and no aircon I found myself running out of steam and making silly mistakes, in INPA I noticed a new error under the AC, which was 'error 52: Energy saving mode', scratched my head for a while and realised that transport mode was enabled, disabled transport mode and the error cleared leaving no error codes under the AC and also the clutch now engages and disengages when controlling from the AC interface in the car, or in INPA.

I think what you just said though @upallnight confirms my suspicion, in that the compressor is done and needs replacing, Come to think of it the low lines were not even cold when running on max, and also when I was looking at the gauges in the garage after it had been filled, the PSI wasn't fluctuating with the AC on max which I would expect it to, I cannot remember the figures but if memory serves me correctly the low pressure should move between 25 to 40ish depending on the cycle....?

I have cancelled the order for the low pressure sensor, and ordered a new compressor instead with the hope I can put this one to bed and move onto the next job!

Unlike home AC, the low-side pressure on a car AC system will only fluctuate when the engine speed is changing. If you observed the reading with the engine at a constant idle, the gauge will not fluctuate, not unless the compressor is cycling on and off.

I would verify the compressor is the problem by having the shop hookup their gauges and observe the low and high side readings. If the high side reading is below 200 psi (sorry us Yanks across the pond is still stuck on the English system of measurement) the compressor is the problem. In order for an AC system to work, there has to be a pressure differential. When installing a new compressor, make sure to use new o-rings at the fittings and make sure the o-rings are lubed with the correct refrigerant oil.

Good Luck Mate.

nigeyboy · #7 08-06-2018, 01:38 PM

I’d just replace the Final Stage Resistor - cures most AC issues.

Sent from my iPad using Tapatalk Pro

RoryK · #8 08-29-2018, 06:13 AM

Well this issue is sorted, I am now enjoying ice cold AC in my e53, although typical its fixed after the heatwave we had here in the uk...

Anyway the compressor had failed which seems like a common Calsonic Kansi issue, replaced it with a new unit and all is good! what a pain, but glad I stuck with it and the wild goose chase of red herring issues.

Hopefully this thread will help another poor soul out there with similar issues, just took some patience and logical thinking to solve this one.

AlanGunn · #9 08-29-2018, 06:51 AM

Nice to get a follow up on the fix.
Thanks.

white_335i · #10 08-29-2018, 08:06 PM

Quote:

Originally Posted by RoryK

Well this issue is sorted, I am now enjoying ice cold AC in my e53, although typical its fixed after the heatwave we had here in the uk...

Anyway the compressor had failed which seems like a common Calsonic Kansi issue, replaced it with a new unit and all is good! what a pain, but glad I stuck with it and the wild goose chase of red herring issues.

Hopefully this thread will help another poor soul out there with similar issues, just took some patience and logical thinking to solve this one.

Good job on finding and fixing the issue. Which compressor did you buy? I need to replace the compressor in my car and trying to figure out which one to get.

Sponsored Links