Central locking and cruise control

Sigold83 · 24th October 2017, 11:51

Hi,

I have recently acquired a ZT-T+. It is a 2003 model and is a great drive. However, there are a couple things that bother me. I am not sure if both are linked with the ECU, so some advice would be great.

The central locking works to unlock via the fob and key lock. It will lock using the internal lock button too. However, the key will not lock centrally with the fob or the key.

The second thing is the cruise control doesn’t work. It switches on, but it will not set speeds etc.

I wonder if they are both related to the ECU, and if replacing it or resetting it will work.

Regards

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Avulon · 24th October 2017, 12:19

Locking is controlled from the BCU (Body Control Unit). I'd suggest you look there first. It will no doubt be suggested that you try disconnecting the battery for 20 minutes to allow the system to fully reset. So do that, and while the battery is disonnected give it a top-up charge.

RE: cruise control, do you know if this was an original fitment or retro-fitted? Without any other errors (e.g. abs fault ) showing then a check by T4 diagnostics would be indicated.

Sigold83 · 24th October 2017, 13:30

Quote:

Originally Posted by Avulon

Locking is controlled from the BCU (Body Control Unit). I'd suggest you look there first. It will no doubt be suggested that you try disconnecting the battery for 20 minutes to allow the system to fully reset. So do that, and while the battery is disonnected give it a top-up charge.

RE: cruise control, do you know if this was an original fitment or retro-fitted? Without any other errors (e.g. abs fault ) showing then a check by T4 diagnostics would be indicated.

The cruise control is factory fitted. With a button on the dash between the heated seats buttons, and controls on the steering wheel.

Where would i find the bcu? And would i need to deactivate anything when disconnecting the battery?

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Avulon · 24th October 2017, 16:18

Before disconnecting the battery make sure that you have the radio code (or have de-activated the radio code) Check over in the ICE section of forum for info on radios. If you have highline then to avoid risk of damage do make sure that the navigation unit in the boot is fully shutdown before disconnecting the battery. (any door open or close will start it up again! be warned!).

The bcu is behind the glove box - no need to access it unless changing it or checking wiring.

Two thoughts on cruise control. (and this is only from reading here)

It won't activate 'set' below 30mph
any activation of brake or clutch will unset it.

Mickyboy · 24th October 2017, 17:42

Ref: cruise control
Make sure that the switches behind the brake and clutch pedals are fully clicked out otherwise it won’t activate
Mick

clf · 24th October 2017, 18:14

To add to what Avulon has said, if it works after the 'battery reset' but then reverts back to not working once again after locking up, it could be a fuse. When I bought my car the previous owner had lived with it like this for two years, even wanting to buy a new BCU and pay to have it programmed for me. I discovered a post by another member on here Beneit, describing the same issue. It turned out to be a 7.5 amp fuse (brown). I cannot remember the location I am afraid. But once that was replaced, the central locking worked correctly, and has done since.

Sigold83 · 24th October 2017, 20:04

Quote:

Originally Posted by clf

To add to what Avulon has said, if it works after the 'battery reset' but then reverts back to not working once again after locking up, it could be a fuse. When I bought my car the previous owner had lived with it like this for two years, even wanting to buy a new BCU and pay to have it programmed for me. I discovered a post by another member on here Beneit, describing the same issue. It turned out to be a 7.5 amp fuse (brown). I cannot remember the location I am afraid. But once that was replaced, the central locking worked correctly, and has done since.

Sounds promising...... if only the location would come to mind?.. 😏

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LeRich · 24th October 2017, 20:19

Re the locking - check your fuses. My old ZT would unlock from the fob,key and lock but would only lock from the button/key. I assumed the lock was faulty but it turned out to be a blown fuse (can't tell you which one from memory).

clf · 24th October 2017, 20:38

Quote:

Originally Posted by Sigold83

Sounds promising...... if only the location would come to mind?.. 😏

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I have had a look at the fuse box diagram, I was mistaken about it being a 7.5amp fuse, rather it being a 5 amp (brown). I cannot recall which fuse it was, however, after you follow Avulon's instructions for the battery reset, you can rule my theory out, but checking if the central locking works, and then fails again after restarting the car.

I cannot remember which fuse it was, because I did not take a note of the post, and resorted to removing all of the 5 amp fuses and replacing them lol.

clf · 25th October 2017, 00:57

Found the post

https://the75andztclub.co.uk/forum/s...d.php?t=128868

Although I am not sure it was fuse 36 on my car (they changed) , check it anyway.

Reading this again, some other things begin to make sense. One being a faulty alarm sounder, which apparently had caused the blown fuse. So it could be worth checking yours too.

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24th October 2017, 11:51	#1
Sigold83 Newbie MG ZT-T Join Date: Jun 2017 Location: Wiltshire Posts: 6 Thanks: 0 Thanked 2 Times in 2 Posts	Central locking and cruise control Hi, I have recently acquired a ZT-T+. It is a 2003 model and is a great drive. However, there are a couple things that bother me. I am not sure if both are linked with the ECU, so some advice would be great. The central locking works to unlock via the fob and key lock. It will lock using the internal lock button too. However, the key will not lock centrally with the fob or the key. The second thing is the cruise control doesn’t work. It switches on, but it will not set speeds etc. I wonder if they are both related to the ECU, and if replacing it or resetting it will work. Regards Sent from my iPad using Tapatalk

24th October 2017, 12:19	#2
Avulon This is my second home 1.8t Tourer Join Date: Oct 2011 Location: Tanelorn Posts: 4,830 Thanks: 956 Thanked 1,148 Times in 916 Posts	Locking is controlled from the BCU (Body Control Unit). I'd suggest you look there first. It will no doubt be suggested that you try disconnecting the battery for 20 minutes to allow the system to fully reset. So do that, and while the battery is disonnected give it a top-up charge. RE: cruise control, do you know if this was an original fitment or retro-fitted? Without any other errors (e.g. abs fault ) showing then a check by T4 diagnostics would be indicated. __________________ Need a T4 ?: T4 Owners Map thanks to Stevestrat ( use at your own risk) Where?: https://en.wikipedia.org/wiki/Tanelorn Mods/Retrofits: PCV vortex 'filter'; bluetooth; inline thermostat; reversing sensors; plenum spyhole ; headlamp washers ; Diy mp3 player replacing CD multichanger; FBH with remote; Headlamp washers; black/chrome front grille, rear blind; Xenon projectors To do: puddle lights; 2 Din cd/nav to fit; boot release button

24th October 2017, 16:18	#4
Avulon This is my second home 1.8t Tourer Join Date: Oct 2011 Location: Tanelorn Posts: 4,830 Thanks: 956 Thanked 1,148 Times in 916 Posts	Before disconnecting the battery make sure that you have the radio code (or have de-activated the radio code) Check over in the ICE section of forum for info on radios. If you have highline then to avoid risk of damage do make sure that the navigation unit in the boot is fully shutdown before disconnecting the battery. (any door open or close will start it up again! be warned!). The bcu is behind the glove box - no need to access it unless changing it or checking wiring. Two thoughts on cruise control. (and this is only from reading here) It won't activate 'set' below 30mph any activation of brake or clutch will unset it. __________________ Need a T4 ?: T4 Owners Map thanks to Stevestrat ( use at your own risk) Where?: https://en.wikipedia.org/wiki/Tanelorn Mods/Retrofits: PCV vortex 'filter'; bluetooth; inline thermostat; reversing sensors; plenum spyhole ; headlamp washers ; Diy mp3 player replacing CD multichanger; FBH with remote; Headlamp washers; black/chrome front grille, rear blind; Xenon projectors To do: puddle lights; 2 Din cd/nav to fit; boot release button

24th October 2017, 17:42	#5
Mickyboy SERVICING AND DEALER DIAGNOSTICS MG ZT CDTI 135 + & MGZT CDTI AUTO 160 & ROVER 75 TOURER CDTI 160 TROPHY YELLOW Join Date: Aug 2013 Location: Hernebay Posts: 4,331 Thanks: 818 Thanked 2,414 Times in 1,141 Posts	Ref: cruise control Make sure that the switches behind the brake and clutch pedals are fully clicked out otherwise it won’t activate Mick __________________ [SIGPIC][/SIGPIC] T4 Owner Jobs done : new UBP, Spy hole mod, Rear hub(wheel bearing),plenum cleaned and emptied, Inline thermostat fitted,Full service, In car Digital tv/DVD Bluetooth Satnav etc, Replaced UBP, Restored headlights,Fixed airbag connection.replaced HP pump,replaced rear light seals,changed intercooler O rings. Jobs to do: ,replace drivers lock,.[/SIZE]

24th October 2017, 18:14	#6
clf This is my second home MG ZT CDTi Join Date: Jan 2014 Location: carrick Posts: 7,859 Thanks: 3,494 Thanked 2,657 Times in 1,973 Posts	To add to what Avulon has said, if it works after the 'battery reset' but then reverts back to not working once again after locking up, it could be a fuse. When I bought my car the previous owner had lived with it like this for two years, even wanting to buy a new BCU and pay to have it programmed for me. I discovered a post by another member on here Beneit, describing the same issue. It turned out to be a 7.5 amp fuse (brown). I cannot remember the location I am afraid. But once that was replaced, the central locking worked correctly, and has done since. __________________ It is not gloss primer .............. it is duct tape silver!

24th October 2017, 20:19	#8
LeRich Posted a thing or two Rover 75 Cont SE 1.8T Join Date: Aug 2010 Location: Cheshire Posts: 1,082 Thanks: 215 Thanked 232 Times in 178 Posts	Re the locking - check your fuses. My old ZT would unlock from the fob,key and lock but would only lock from the button/key. I assumed the lock was faulty but it turned out to be a blown fuse (can't tell you which one from memory). __________________ Rover 75 1.8T Contemporary SE Auto Starlight Silver MBB

25th October 2017, 00:57	#10
clf This is my second home MG ZT CDTi Join Date: Jan 2014 Location: carrick Posts: 7,859 Thanks: 3,494 Thanked 2,657 Times in 1,973 Posts	Found the post https://the75andztclub.co.uk/forum/s...d.php?t=128868 Although I am not sure it was fuse 36 on my car (they changed) , check it anyway. Reading this again, some other things begin to make sense. One being a faulty alarm sounder, which apparently had caused the blown fuse. So it could be worth checking yours too. Sent from my SM-A310F using Tapatalk __________________ It is not gloss primer .............. it is duct tape silver! Last edited by clf; 25th October 2017 at 02:04..