ATC heater diagnostic not working

Fishytroll66 · 18th September 2017, 18:42

Hi all, I am trying to use the heater diagnostics = press auto and distribution buttons together and turn ignition from 0 - 2? Nothing happens at all, any help appreciated.

The blender motor is either fully closed or fully open, the distribution motor and blower speeds are fine, matrix inlet and outlet are both scalding hot, yet after 20 miles or so the heater is pants.
It is a cdti, so I know getting heat into them is an issue but his is baffling me. I've got the inline thermostat from DGMRS too.

T-Cut · 19th September 2017, 07:36

Do you mean the heater pipes cool down? If so, then the diagnostic system won't identify the cause, which is a lack of coolant flow through the matrix. If this seems applicable, I'd suggest you read up about bleeding the diesel cooling system. It may be caused by an air lock of circulating air bubbles. Fitting the in-line stat may have initiated the problem

TC

Fishytroll66 · 19th September 2017, 19:17

Hi Tcut and thanks for your reply, initially the heating is very good through the vents, but after 20 miles or so the air blowing through the vents becomes almost cold -even in manual mode.
The ATC seems to reduce the fan speed when the heater is set to say 21 and the external temp is saying 15? Yesterday I checked for movement of the motor (temp control in left footwell), basically that is either fully open or fully closed - is that normal?
I have the inline thermostat from DGMRS and engine temp via OBD is 94- 96 if I recall, there is also a good return flow to the header tank and no sign of air.

Sorry for the S.A, but it is baffling me. Could it be the interior ambient temperature sensor?

SD1too · 19th September 2017, 19:41

Quote:

Originally Posted by T-Cut

... I'd suggest you read up about bleeding the diesel cooling system.

And here are the official instructions Paul. Do this before speculating about more obscure faults.

Simon

T-Cut · 19th September 2017, 19:52

Quote:

Originally Posted by Fishytroll66

The ATC seems to reduce the fan speed when the heater is set to say 21 and the external temp is saying 15?

The ATC is adjusting airflow into the cab to maintain the setting you've chosen (Automatic Temperture Control) If the fan speed didn't adjust it wouldn't do that. The flaps for mixing heated and incoming air also adjust accordingly.

Quote:

Yesterday I checked for movement of the motor (temp control in left footwell), basically that is either fully open or fully closed - is that normal?

I dunno. Your ATC diagnostics not working seems to point to a system fault somewhere. Couldn't guess. Maybe contact one of the T4 guys.
Is this what you're following: https://www.the75andztclub.co.uk/for...d.php?t=162975

Quote:

I have the inline thermostat from DGMRS and engine temp via OBD is 94- 96 if I recall.

Few diesels reach these temperatures, even with an inline stat. Looks unusual.

Quote:

There is also a good return flow to the header tank and no sign of air.

The header tank isn't in the cooling circuit apart from when you're filling/bleeding the head. When do you see the 'good return flow'?

Quote:

Sorry for the S.A, but it is baffling me. Could it be the interior ambient temperature sensor?

I doubt it.

Does the heater matrix itself (both pipes) go cool when the heating stops? You should park up when it happens and feel the pipes.

TC

Fishytroll66 · 20th September 2017, 12:45

Gents, I bow to your superior knowledge. After letting the car sit at 2000 rpm with the header tank cap off, whilst I read war and peace, I kept getting gushes of air, the level would rise and fall quite often, then another gush of air, I left it running at 2000 rpm until the rad fan kicked in, let it cool and preceded to top it up with coolant - 3 litres later! Heater is now fantastic.

Just goes to show, don't get baffled, get advice

Thanks peeps!

18th September 2017, 18:42	#1
Fishytroll66 Avid contributor MG ZT -T Join Date: Feb 2016 Location: Rhuddlan Posts: 115 Thanks: 31 Thanked 13 Times in 13 Posts	ATC heater diagnostic not working Hi all, I am trying to use the heater diagnostics = press auto and distribution buttons together and turn ignition from 0 - 2? Nothing happens at all, any help appreciated. The blender motor is either fully closed or fully open, the distribution motor and blower speeds are fine, matrix inlet and outlet are both scalding hot, yet after 20 miles or so the heater is pants. It is a cdti, so I know getting heat into them is an issue but his is baffling me. I've got the inline thermostat from DGMRS too. __________________ Paul (AKA Fishytroll)

19th September 2017, 07:36	#2
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	Do you mean the heater pipes cool down? If so, then the diagnostic system won't identify the cause, which is a lack of coolant flow through the matrix. If this seems applicable, I'd suggest you read up about bleeding the diesel cooling system. It may be caused by an air lock of circulating air bubbles. Fitting the in-line stat may have initiated the problem TC Last edited by T-Cut; 19th September 2017 at 07:38..

19th September 2017, 19:17	#3
Fishytroll66 Avid contributor MG ZT -T Join Date: Feb 2016 Location: Rhuddlan Posts: 115 Thanks: 31 Thanked 13 Times in 13 Posts	Hi Tcut and thanks for your reply, initially the heating is very good through the vents, but after 20 miles or so the air blowing through the vents becomes almost cold -even in manual mode. The ATC seems to reduce the fan speed when the heater is set to say 21 and the external temp is saying 15? Yesterday I checked for movement of the motor (temp control in left footwell), basically that is either fully open or fully closed - is that normal? I have the inline thermostat from DGMRS and engine temp via OBD is 94- 96 if I recall, there is also a good return flow to the header tank and no sign of air. Sorry for the S.A, but it is baffling me. Could it be the interior ambient temperature sensor? __________________ Paul (AKA Fishytroll)

20th September 2017, 12:45	#6
Fishytroll66 Avid contributor MG ZT -T Join Date: Feb 2016 Location: Rhuddlan Posts: 115 Thanks: 31 Thanked 13 Times in 13 Posts	re heater issue Gents, I bow to your superior knowledge. After letting the car sit at 2000 rpm with the header tank cap off, whilst I read war and peace, I kept getting gushes of air, the level would rise and fall quite often, then another gush of air, I left it running at 2000 rpm until the rad fan kicked in, let it cool and preceded to top it up with coolant - 3 litres later! Heater is now fantastic. Just goes to show, don't get baffled, get advice Thanks peeps! __________________ Paul (AKA Fishytroll)