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Member
Joined: Aug 06 2019
Posts: 99

Hi, I would like to ask for a bit of advice in relation to the never-ending issue of the book symbol on the HEVAC display.

I have read lots of posts giving solutions to the many issues which affect the air-con and ventilation in the P38, but I would like to see if these solutions are directly relevant to the reason the book symbol keeps appearing on the display in my P38.

I have replaced the pollen filters recently, cleaned and hoovered out the plenum area [?], fitted a new plenum filter, but the symbol is stillon the display.

The thing is, when I turn off the ignition, leave the car parked for a day or so and go back out in the vehicle then the symbol is not on the display, it only appears after about 15 minutes or so after setting off. Is this the air-mix flaps getting stuck, or will I need to go through the whole job of replacing the whole blower assembly.

The HEVAC display seems to clear the book symbol each time the ignition is turned off, but is this only the BeCM checking the system and then flagging the issue ?

I was hoping [!!!!!] that this may only be the air flap motor getting stuck, as described elsewhere, but I am wondering whether this is too simple a solution.

Any advice is appreciated, as I couldn't get cold air for the last few days in the hot weather.

Pierre3.

Or am I asking too generalised a question ?

Member
Joined: Dec 29 2016
Posts: 443

It could be a number of things causing the book symbol to appear from low refrigerant in the air con system to knackered blend motors.

The only real way to find out what is upsetting it and causing the symbol to appear is to have the codes read from the HEVAC ECU. That'll give you the best indication of where to look for the fault.

David.

Member
Joined: Apr 23 2019
Posts: 571

+1.
hevac goes through a basic self test each time it is switched on - which includes moving the blend flaps. If they were stuck the symbol wd most likely come on straight away. The fact that it comes on later implies it is something else eg ac related, which the ECU is only requesting later on, in real life, doesn't work, and then throws up the symbol.
I'm guessing you have an ac issue...clutch engaging? if not, is it magnetised, if not can you engage it with 12v supplied direct to the compressor? do you now get cold air?

Member
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Joined: Dec 30 2015
Posts: 4913

+2, without diagnostics to see what it is that is bringing the book on, you can spend weeks chasing your tail. You need to read the fault and it will tell you immediately if it is blend motors, blowers, AC clutch, etc then deal with the fault. Everything (except the recirculate flaps) feedback to the HEVAC so it is detecting a fault somewhere but you need to know where.

Member
Joined: Feb 11 2018
Posts: 398

Diesel doesn't care if ac has gas or not. Mine was running for several years without gas. Now it's fixed which was lovely in the hot weather.

Member
Joined: Aug 06 2019
Posts: 99

Hi, many thanks for the advice, I thought, all right, that I was asking a bit to much of a general question as I have already read about lots of questions and answers about the book symbol issue.

That's an interesting point about the diesel not looking for AC refrigerant.

I suppose that I am not absolutely sure that I know what to look for, or expect to happen when the air-con is running [or not !]. I will run the engine up at the weekend and get it hot, and then go through the different settings and see what happens. Again, being honest, I am not sure whether I can justify £400/500 for a plug in diagnostic tool, but as has been mentioned without it I could be going around in circles. Do all the diagnostic tools that are advertised, work with the HEVAC system, or is it only Nanocom or Evo ?

I might ask a guy I have had do some work on the vehicle if he can use his diagnostic machine to check the HEVAC system, and see if he can identify the problem. Although having just spent €2800 on getting the front suspension and steering links replaced, and new brake lines, I think that it may need to be on the long finger.

I may see if I can check the blend motors over the weekend, just to see if they are doing what they should.

Thanks for the help.

Pierre3.

Member
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Joined: Dec 30 2015
Posts: 4913

If it was a blend motor, chances are the book would pop up just after you switch the ignition on. If you turn the ignition on and listen carefully, you will hear the blend motors being driven from one end of their travel to the other. If an error is logged, the book will appear immediately. If it is an AC clutch issue, then the book will appear when it tries, and fails, to engage the AC compressor clutch. If you start the car then press the AC OFF button, it will not try to engage the AC compressor clutch so if it is that causing the book to appear it won't, it will remain off.

That will at least give you a couple of things to check.

Member
Joined: Aug 06 2019
Posts: 99

Thanks, Gilbert, for the advice. I will have to wait for the weather to improve, as unfortunately, I have to do this on the drive !

Pierre3.

Member
Joined: Feb 25 2020
Posts: 209

Money wisest spent was on the Nanocom. Actually, I've budgeted in when I was set on a RRP38, wouldn't be without.
You will never lose that expense ....

My HeVAC was without book symbol, but was not running well anyway. I've discovered once I took everything apart my flaps were literally disintegrated, hence the poor flow - or lack of, depending on the position required. You never know ...

Member
Joined: Aug 06 2019
Posts: 99

Thanks for your advice, I will give some thought to buying the Nanocom unit.

Pierre3.