Rev counter and temp guage not working

Allan Vincent · 29th December 2020, 08:57

Hi guys, happy new year to all, let's hope it's an improvement on last one. My beloved 75's tach and temp guage has stopped working. It happened a couple of years ago and a battery change sorted it out. It started playing up again a few weeks ago, by the 2 guages not working, then they would start up after a few miles of driving. Gradually the time taken and the miles driven took longer and longer for the guages to work. So I guessed the battery had packed up. Fitted a new battery but no joy. If anybody has got some ideas, please let me know, I am not a super technical guy and I'm in my mid 70's so my advice should be tempered with this in mind. Hope somebody can help Cheers, Allan V.

vitesse · 29th December 2020, 13:17

Quote:

Originally Posted by Allan Vincent

Hi guys, happy new year to all, let's hope it's an improvement on last one. My beloved 75's tach and temp guage has stopped working. It happened a couple of years ago and a battery change sorted it out. It started playing up again a few weeks ago, by the 2 guages not working, then they would start up after a few miles of driving. Gradually the time taken and the miles driven took longer and longer for the guages to work. So I guessed the battery had packed up. Fitted a new battery but no joy. If anybody has got some ideas, please let me know, I am not a super technical guy and I'm in my mid 70's so my advice should be tempered with this in mind. Hope somebody can help Cheers, Allan V.

My first step would be to check that the gauges are working as they should. Go to this link: https://www.the75andztclub.co.uk/for...ad.php?t=55585
2. Cluster system test, this will activate the gauges and if it does you can rule out your instrument pack.
You've also got a T4 (Rover diagnostic computer) equipped garage up in Newton Abbot, one of the traders on here, they should be able to help.

Regards

cb750chris · 29th December 2020, 20:43

Following doing the dial checks suggested by vitesse, I would suggest checking your plenum drains, as these symptoms all point to a canbus communications problem, which can be caused by a swimming ecu.
Fingers crossed it isn't this, as by the time you see problems your ecu can be very unwell ��
Good luck

Chris

marinabrian · 29th December 2020, 21:36

CAN messages failure instrument Pack 3 is the answer to the problem Allan.

The part that has failed in your ECM is the interface between the IPK and the DDE, and is no longer available

Your heated rear screen will also be inoperative.

The answer sadly is a replacement ECM, I'm hazarding a guess your car is a manual model, so an NNN100692.

If you need any more information, PM me with a contact number and I'll talk you through what you need to do to sort it out.

Brian

marinabrian · 29th December 2020, 21:57

At least you got a couple of years out of it before the intermittent fault became permanent LINK

I still have the solution though

Brian

Allan Vincent · 30th December 2020, 11:04

Quote:

Originally Posted by vitesse

My first step would be to check that the gauges are working as they should. Go to this link: https://www.the75andztclub.co.uk/for...ad.php?t=55585
2. Cluster system test, this will activate the gauges and if it does you can rule out your instrument pack.
You've also got a T4 (Rover diagnostic computer) equipped garage up in Newton Abbot, one of the traders on here, they should be able to help.

Regards

Thanks for this I''ll give it a go

Allan Vincent · 30th December 2020, 11:06

Quote:

Originally Posted by cb750chris

Following doing the dial checks suggested by vitesse, I would suggest checking your plenum drains, as these symptoms all point to a canbus communications problem, which can be caused by a swimming ecu.
Fingers crossed it isn't this, as by the time you see problems your ecu can be very unwell ��
Good luck

Chris

I keep the Plenum clear and dry, but many thanks for the reply

Allan Vincent · 30th December 2020, 11:09

Quote:

Originally Posted by marinabrian

CAN messages failure instrument Pack 3 is the answer to the problem Allan.

The part that has failed in your ECM is the interface between the IPK and the DDE, and is no longer available

Your heated rear screen will also be inoperative.

The answer sadly is a replacement ECM, I'm hazarding a guess your car is a manual model, so an NNN100692.

If you need any more information, PM me with a contact number and I'll talk you through what you need to do to sort it out.

Brian

Cheers Brian you kindly gave me some invaluable advice last time this happened. What does a ECM replacement cost as a matter of interest

Arctic · 30th December 2020, 12:43

Quote:

Originally Posted by Allan Vincent

Cheers Brian you kindly gave me some invaluable advice last time this happened. What does a ECM replacement cost as a matter of interest

Hi Vincent.
Follow the links

[QUOTE=marinabrian;2856616]At least you got a couple of years out of it before the intermittent fault became permanent LINK

I still have the solution though

trefonix · 3rd January 2021, 13:26

Hi Allan looks like we're very close to each other!

Exeter Road Garage in Newton has a t4 but be warned the dude who runs the place is passionate. No question he knows the cars inside out, though.

I had the exact same issue on my car (temp gauge gone and rev counter), it was fixed by hitting the instrument cluster pretty hard. The instrument cluster is a hub of sorts for the communications bus and if the wires going into the back of it become loose or corroded it can cause your problem.

29th December 2020, 08:57	#1
Allan Vincent Newbie Rover 75 Join Date: Mar 2016 Location: Torquay Posts: 29 Thanks: 17 Thanked 9 Times in 3 Posts	Rev counter and temp guage not working Hi guys, happy new year to all, let's hope it's an improvement on last one. My beloved 75's tach and temp guage has stopped working. It happened a couple of years ago and a battery change sorted it out. It started playing up again a few weeks ago, by the 2 guages not working, then they would start up after a few miles of driving. Gradually the time taken and the miles driven took longer and longer for the guages to work. So I guessed the battery had packed up. Fitted a new battery but no joy. If anybody has got some ideas, please let me know, I am not a super technical guy and I'm in my mid 70's so my advice should be tempered with this in mind. Hope somebody can help Cheers, Allan V.

29th December 2020, 20:43	#3
cb750chris Trader Rover 75 Tourer Join Date: Apr 2011 Location: Portsmouth Posts: 849 Thanks: 201 Thanked 292 Times in 200 Posts	Following doing the dial checks suggested by vitesse, I would suggest checking your plenum drains, as these symptoms all point to a canbus communications problem, which can be caused by a swimming ecu. Fingers crossed it isn't this, as by the time you see problems your ecu can be very unwell �� Good luck Chris __________________ Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics.

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29th December 2020, 21:36	#4
marinabrian MG ZT Join Date: Jan 2011 Location: Newcastle Upon Tyne Posts: 20,151 Thanks: 3,565 Thanked 10,837 Times in 5,718 Posts	CAN messages failure instrument Pack 3 is the answer to the problem Allan. The part that has failed in your ECM is the interface between the IPK and the DDE, and is no longer available Your heated rear screen will also be inoperative. The answer sadly is a replacement ECM, I'm hazarding a guess your car is a manual model, so an NNN100692. If you need any more information, PM me with a contact number and I'll talk you through what you need to do to sort it out. Brian

29th December 2020, 21:57	#5
marinabrian MG ZT Join Date: Jan 2011 Location: Newcastle Upon Tyne Posts: 20,151 Thanks: 3,565 Thanked 10,837 Times in 5,718 Posts	At least you got a couple of years out of it before the intermittent fault became permanent LINK I still have the solution though Brian

3rd January 2021, 13:26	#10
trefonix Newbie Rover 75 Saloon Join Date: Dec 2019 Location: Devon Posts: 29 Thanks: 0 Thanked 10 Times in 6 Posts	Hi Allan looks like we're very close to each other! Exeter Road Garage in Newton has a t4 but be warned the dude who runs the place is passionate. No question he knows the cars inside out, though. I had the exact same issue on my car (temp gauge gone and rev counter), it was fixed by hitting the instrument cluster pretty hard. The instrument cluster is a hub of sorts for the communications bus and if the wires going into the back of it become loose or corroded it can cause your problem.