Hi all! 

I had the TCU module replaced (under warranty) 2 weeks ago on my 2021 Focus ST (1.5 petrol)

A few days ago, the sun popped out and I had the the need to turn on the air con.... but... no cold air... usually you tell if the air con kicks in by hearing the compressor clutch engage, or the engine revs dipping, but couldn't hear anything.

Got it down to my local garage today that provide A/C servicing and repair to try a regas to see if that was the issue. The regas machine said the system had plenty of pressure, but I opted to get it done anyway just incase.

Still no cold air, and no sign of the compressor clutch engaging.

Visual inspection of the A/C system didn't reveal any signs of leaks either.

The garage got the diagnostics connected, but no faults found. They load tested the battery, checked fuses etc, but all fine.

I don't really know if the TCU module has anything to do with the A/C, but it does seem to me very coincidental that the issue has started since it was replaced.

I've contacted the Ford dealership I had the TCU module replaced at, and now the car is no longer in manufactures warranty, they want to charge me £150 to look at it. I asked to speak to the technician that worked on the car, but no, I have to get it booked in.

So, just wondering if there's anyone on here that might have experienced similar issues, or perhaps has the technical knowledge on these TCUs and whether they control any element of the A/C?

Or, is it really a coincidence and I need to do more investigating!?

Cheers!

7 minutes ago, Ryanfsr said:

A few days ago, the sun popped out and I had the the need to turn on the air con.

If you had left it 'on' then you would have know when it stopped working. 🤔

Now time for a word from the A/C sponsor @StephenFord 🤣

14 hours ago, unofix said:

Now time for a word from the A/C sponsor @StephenFord 🤣

LOL, OK, here I am. Still bemuses me that after 40 odd years of being fitted to many UK cars, most folk who have A/C in their car haven't a clue what it does, or, how to use it. It is NOT a temperature thing. The clue is really in the name, it CONDITIONS the air. There is no reason at all not to leave it on all the time. Even in the depths of winter, it will condition the air (remove the moisture) so that all your windows don't condensate up. The temperature gauge is totally separate. You can set it to 25c, or 5c, all with the A/C on. 

Pretty sure you don't switch your home fridge on/off just when you need it. The compressor runs 24/7. Still, when you get it fixed, you'll know what to do with it... 👍

How often do you 'condition' the air in a UK home?

If you live in Florida with 80% humidity then yes, it needs to dry the air to stop you melting into the seats.  In the UK, we generally have fairly comfortable ambient humidity levels.  Very few people air condition homes over here, and those that do certainly don't waste electric leaving it on all year round.

If the windows steam up on a particularly damp morning then by all means switch on the AC...but to leave it on permanently seems unnecessary to me.  Like walking around with an open umbrella 24/7 because it will rain at some point...

9 minutes ago, TomsFocus said:

... Like walking around with an open umbrella 24/7 because it will rain at some point...

Not the best analogy LOL You lose the use of one hand holding the darn thing. My solution, always wear a brimmed hat, leaves both hands free, and protects me from rain when it occurs which it does very often here. Oh, also protects me from the sun 🤣

My favorite Barmah hat...

Yes, I have to agree with Stephens description on how air con should be used.

Don't know about others but, for example, a BMW 3 series G20 models 2019 onwards all run continuously with air con on, ie compressor running.

If you turn the air con off all the flaps close, it all shuts down and no air whatsoever comes into the veh

I can confirm that modern Fords & VW's aren't setup like that.  There are separate buttons to either switch off just the AC, or switch off the whole climate control system.

It's also worth noting that modern cars use variable rate compressors combined with temperature & humidity sensors to limit the load on the engine as much as possible, even though the compressor appears to be running all the time.  So that is more fuel efficient than cars with manual AC and conventional on or off compressors.

Thanks for the replies, but I wasn't asking how I should be using the air con, but more, is the TCU module linked in any way to the A/C. Besides, Ford have gone to the effort of engineering it to allow it to work that work, so surely that's what should be expected, right?

Before it went into Ford it worked great. Since getting the car back from them, we were experiencing a cold spell here in the UK for a week or so, and I can't confirm if the A/C button was lit or not. I just set the car to a comfortable temp and carried on.

Last weekend, the sun came out. Span the temp gauge to low, ensured the A/C light was lit, and waited for the chilled air, but nothing.

I'm going to give Ford a call tomorrow and take the hit for them to try and diagnose it. I'll emphasise though that it was working fine prior to to it being in previously. I just find it odd that no fault code has been logged though, and what's making me think it's related to this TCU module.

10 minutes ago, Ryanfsr said:

Thanks for the replies, but I wasn't asking how I should be using the air con, but more, is the TCU module linked in any way to the A/C. Besides, Ford have gone to the effort of engineering it to allow it to work that work, so surely that's what should be expected, right?

Before it went into Ford it worked great. Since getting the car back from them, we were experiencing a cold spell here in the UK for a week or so, and I can't confirm if the A/C button was lit or not. I just set the car to a comfortable temp and carried on.

Last weekend, the sun came out. Span the temp gauge to low, ensured the A/C light was lit, and waited for the chilled air, but nothing.

I'm going to give Ford a call tomorrow and take the hit for them to try and diagnose it. I'll emphasise though that it was working fine prior to to it being in previously. I just find it odd that no fault code has been logged though, and what's making me think it's related to this TCU module.

Do you have Forscan?  The cars state of charge is probably out of sync with the actual battery charge since the garage did the update.

No I don't I'm afraid. Probably something I should consider getting though.

Looks like the Android version is good if you don't wish to do any programming. Would that be enough to view state of charge to confirm the issue?

1 minute ago, Ryanfsr said:

No I don't I'm afraid. Probably something I should consider getting though.

Looks like the Android version is good if you don't wish to do any programming. Would that be enough to view state of charge to confirm the issue?

Yes.  But if you want to try an immediate SOC reset, just disconnect the battery for an hour or so.  That should reset all modules and the battery SOC together.

1 hour ago, TomsFocus said:

Yes.  But if you want to try an immediate SOC reset, just disconnect the battery for an hour or so.  That should reset all modules and the battery SOC together.

Thanks! I'll give this a go first 

1 hour ago, Ryanfsr said:

Looks like the Android version is good if you don't wish to do any programming. Would that be enough to view state of charge to confirm the issue?

The phone versions of FORScan are the same as the Windows version with the exception that you can't make any programme changes. The phone versions still allows you to clear DTC's, and reset service indicators, and oil life reminders.

On 4/7/2024 at 8:59 PM, unofix said:

FORScan (for use with Windows Laptop) : https://forscan.org/download.html

It's what many Ford owners use including some Ford technicians.

vLinker FS, cable for laptop: https://www.amazon.co.uk/Vgate-vLinker-Adapter-FORScan-MS-CAN/dp/B0952P4MLP

vLinker FD, for android phone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H82WC8L

vLinker FD+, for iPhone: https://www.amazon.co.uk/Vgate-Bluetooth-vLinker-Scanner-Diagnostic/dp/B08H8JHWP2

 

Search Tag:   FORScan123

 

20 hours ago, StephenFord said:

LOL, OK, here I am. Still bemuses me that after 40 odd years of being fitted to many UK cars, most folk who have A/C in their car haven't a clue what it does, or, how to use it. It is NOT a temperature thing. The clue is really in the name, it CONDITIONS the air. There is no reason at all not to leave it on all the time. Even in the depths of winter, it will condition the air (remove the moisture) so that all your windows don't condensate up. The temperature gauge is totally separate. You can set it to 25c, or 5c, all with the A/C on. 

Pretty sure you don't switch your home fridge on/off just when you need it. The compressor runs 24/7. Still, when you get it fixed, you'll know what to do with it... 👍

Mine is never off, middle of winter or middle of summer

13 hours ago, TomsFocus said:

Yes.  But if you want to try an immediate SOC reset, just disconnect the battery for an hour or so.  That should reset all modules and the battery SOC together.

Tried this this morning, but no luck unfortunately.

Booked into Ford now next Monday. Spoke to the manager and they're doing the investigation free of charge due to the previous works carried out, so I'm happy with that. Just a case of wait and see now.

Thanks for the FORScan links though @unofix. I've ordered the Android dongle 

Well..... I'm baffled!

Got in the car to head home today, started up, heard the click of the A/C compressor, and icy cold air started flowing out of the vents!

I've done nothing different. It just appears to have fixed itself!