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Discussion Starter · #1 ·
I have a 2002 PD130 1.9 TDi Golf Mk 4.

My aircon has been playing up for months. It is NOT a climatronic aircon (I have an AC button plus 4 fan speeds and a hot to cold rotary dial).

I had previously disconnected/reconnected the 2-pin connector next to the compressor and 4-pin connector to the left of the battery bottom and disconnected the battery to check the fuses on top of the battery. After reassembly and reconnecting the battety the aircon started working for a while. Ice cold air in the cabin. I assumed it was a dodgy connector that I had now correctly reseated.

Then it stopped working again.

Last week I unplugged the compressor 2-pin connector and checked continuity to the 4-pin connector to the left of the battery bottom. No problems. I then checked continuity of the same 2 pins in the 4-pin connector to the 14-pin connector to the Fan Contol Module (after taking the passenger headlight back cover, battery and battery box out). No problems. I reassembled everything and the aircon worked again. I could see the aircon clutch engage/disengage when I pressed the AC button on/off. The low speed fans came on correctly. I got ice cold air in the cabin.

Two days later the aircon stopped working again (no more ice cold air). I confirmed that the aircon cluch was not engaging with the AC button on (and light lit up). I disconnected the battery for 10 minutes and then reconnected it. The aircon started working again. I could see the aircon clutch engage/disengage when I pressed the AC button on/off.

I am sort of expecting it to fail again in a few days time like the last time. I am wondering if all my previous "fixes" worked because I had "turned the car off and on again", but some device eventually registers a fault which disables the aircon? Is it likely to be a faulty FCM or something else?

I do not have VCDS. I do have an ODB2 reader but, for some reason, it does not work on the Golf, even though the car is from 2002. Would this cable <ebay link> be able to connect to VCDS Lite and help me get diagnostic codes?

Thanks for reading
Darren
 

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Hi there. I have the same - a PD130 2002. OBD2 readers don't generally work on our cars - if I remember correctly ours are pre CAN bus (I really may have got that wrong) although they have OBD2 ports they don't have the standard adopted on later cars. Something like that anyway! I've had a look at your eBay link - I can't vouch for that exact cable but it looks exactly like the one I used successfully with VCDDS lite. I see in the details though it says "Operating Software Compatibility: Windows 98SE / ME / 2000 / NT and XP." - do you have a PC with old Windows on it? Does VCDS light even work anymore without some sort of subscription? I have a fully paid-up VCDS with a cable, bought from Gendan, it's paid for itself countless times but I aim to keep the car as a cheap daily for some while......
 

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That cable will work, just download VCDS lite from Ross tech to use alongside it.

Either something is needing a reset or it's just a coincidence. For the cost of an FCM, I'd replace it. They go bad so often, and brand new Febi ones can be had for around £30. Second hand for £10.
 

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Discussion Starter · #4 ·
Thanks for the advice guys. I drove the car today and she enough the aircon clutch did not engage again. I'll get the cable see if I can see any codes and get a second hand FCM. Hopefully that should get me somewhere. I could also use the cable on my daughter's 2004 Transporter T5.

I will report back in a few weeks.
Darren
 

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Discussion Starter · #5 ·
That cable will work, just download VCDS lite from Ross tech to use alongside it.

Either something is needing a reset or it's just a coincidence. For the cost of an FCM, I'd replace it. They go bad so often, and brand new Febi ones can be had for around £30. Second hand for £10.
You probably were right about the coincidence. I unplugged the battery again for 10 minutes and clutch did not engage. I'll have to wait until the cable and the FCM arrives. I have a long 2.5 hour journey next Sunday (and back again) so hopefully I can get it fixed again.
 

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Discussion Starter · #6 ·
I got the KKL cable and got it talking with VCDS Lite (un-registered). I recorded several fault codes, wrote them down, then cleared them all. I also got the new second hand FCM and installed it (removed passenger headlights "back covering plate?", battery, battery box, managed to unscrew the old FCM and take off the connectors, prised them off with screwdriver at the very end of the connectors (opposite end to the wiring), with access only from the top of the car, i.e. no jacking the car up.

Refitted everything and the aircon is working again. Not sure if it is the new FCM, because everything I have done is what I originally did with the old FCM (except clear fault codes). However with the old FCM the aircon stopped again after a few days. So it will be about a week before I know one way or the other. I will also then check the fault codes and see if any have reappeared.

I'll keep you updated.

Darren
 

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Discussion Starter · #7 ·
After having previously cleared the fault codes on my Golf Mk4 I thought I would do a full scan of the car. Last night I sat in my car for about 40 minutes with VCDS-Lite running "Control Module Finder" to detect all available modules for my car. I then checked for any fault codes. I only have 17664 fault code now. 17664/P1256 - Ross-Tech Wiki indicates that the G62 sensor is known to go faulty on this car, although reading the possible symptoms I can't say that I have noticed any of them.

I am thinking that I should try and drive around with VCDS-Lite inspecting the temperature sensor and see if it increases in temperature after starting the car from cold. Not sure if this is possible with VCDS-Lite (unregistered version).

Does anyone have any experience of this G62 issue? YouTube videos show the replacement of the part is relatively simple (lose a bit of coolant). Does anyone know the part number?

Thanks
Darren
 

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Discussion Starter · #8 ·
Well Sunday came when I need my car for a long journey. Flipping AirCon didn't work. I cleared the 17664 fault code then set off. When I got home sure enough the 17664 fault had reappeared. Also I checked group 001 from Module 01 - Engine and saw that the coolant temperature was reading 64 degrees even after a 90 mile drive home. When I tested it previously I noticed that I only ever got to 70 degrees. In all cases the temperature dial on the dashboard indicated 90 degrees. The VCDS-Lite page says this value should read 80-110 degrees. The 17664/P1256 - Ross-Tech Wiki says this fault is either bad wiring or faulty sensor.

I am not sure where the wiring goes to to try and check whether it is bad wiring. I am more inclined to think it is the sensor as it does generate temperature readings. However, if this is a resistance thing then I guess bad wiring could change the resistance. I found on What exactly does the G62 Coolant Temp Sensor do? (am I allowed to link to other sites?) that the G62 is used when starting the car. I then tried googling G62 and aircon and could not find any. Does this mean G62 has no affect on the aircon and since my car starts OK then I can safely ignore this issue (for the time being)? Alternatively does low temperature from G62 mean the car thinks the engine is cool so doesn't run the fans which then means the aircon doesn't run?

I then started thinking what would stop the aircon clutch from engaging. Low aircon gas? I can't see any fault codes.

In my VDS-Lite I cannot connect to 08 HVAC module. I don't have a climatronic AC, just one with a cold/hot rotary dial and a fan switch with settings 0 (Off), 1, 2, 3, 4. Should I be able to connect to 08 HVAC module (or isn't there one on my car)?

Thanks
Darren
 
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