AnMgZsUser
Standard Member
- Joined
- Aug 30, 2022
- Messages
- 15
- Reaction score
- 19
- Points
- 7
- Location
- Cambridgeshire, UK
- Driving
- MG ZS EV
Well, it happened. 22 plate MG ZS EV. I don't know what triggered it but this was my restart sequence:
When the car started, all the alerts came... the most significant, that wouldn't go away even through a power cycle was:
The brakes were rock solid - no vacuum at all. I have a "good" ODB2 BT adaptor (Vgate icar pro) and tried a few different apps, but none could communicate with the car (something I'd dearly love to know why... if anyone knows what protocol should be used, or how to coerce that thing to work please let me know).
The MG Assistance (AA) was called, and once they arrived they could communicate with the car with their bosch kit, but unlike others have experienced, this did not make the problem go away, even clearing the faults they could see. They also tried disconnecting the 12v battery for at least 5 minutes, the problem was still there. I went to get a drink and let the AA guy tinker with it, thankfully being the sort not to give up on a problem. When I came back he was about to try something daunting...
Since the "vacuum system fault" was evident with the rock solid brakes, he decided to try to manually power the vacuum pump, to see if that was working. He did this by removing the pump connector from the loom and applying 12v across it - side note: I didn't question this, if the dealership said that he broke it more I'd be having choice words with MG about their choice of "assistance" provider and insisting since it fell under the assistance, it's still on them to fix it. When he did this, all the alerts magically went away. He plugged the pump back into the loom, I pressed the brake and the pump kicked in as it should.
Manually powering the vac pump in fact fixed the problem.
His theory was that the software got into a "chicken and egg" scenario, where either it believed there was a switch problem because there was no vacuum, or the switch was actually stuck because there was no vacuum, and therefore wouldn't start the pump, and the act of forcing the pump fixed the issue. I've emailed my local dealer to see what they say on the matter. But I've experimented (a bit), and driven 35 miles since and no problem reoccurrence. His suggestion is that should it happen next time, tap the vacuum switch (he pointed it out), disconnect and reconnect the pump, and if that doesn't work, call them and try to repeat the fix.
That's my story. I certainly won't be fiddling with the wiring myself, and wouldn't recommend people do so if they experience the same sort of thing. Best to call MG Assistance and let them have a crack at it...
- switching car on with two taps of power and no brake pedal, so that I could tap "finish charging" on the entertainment panel
- pulling the power cord
- tapping the power, but having forgotten to press the brake, had to then press the break and press power again. Likely this was < 2 second gap. From what I've read online this "quick stop/start cycle" might be the culprit. I've certainly had a similar situation in the past where stopping and starting the car too fast caused an issue.
When the car started, all the alerts came... the most significant, that wouldn't go away even through a power cycle was:
- limited power, limiting speed
- vacuum system fault
- vehicle control system fault
The brakes were rock solid - no vacuum at all. I have a "good" ODB2 BT adaptor (Vgate icar pro) and tried a few different apps, but none could communicate with the car (something I'd dearly love to know why... if anyone knows what protocol should be used, or how to coerce that thing to work please let me know).
The MG Assistance (AA) was called, and once they arrived they could communicate with the car with their bosch kit, but unlike others have experienced, this did not make the problem go away, even clearing the faults they could see. They also tried disconnecting the 12v battery for at least 5 minutes, the problem was still there. I went to get a drink and let the AA guy tinker with it, thankfully being the sort not to give up on a problem. When I came back he was about to try something daunting...
Since the "vacuum system fault" was evident with the rock solid brakes, he decided to try to manually power the vacuum pump, to see if that was working. He did this by removing the pump connector from the loom and applying 12v across it - side note: I didn't question this, if the dealership said that he broke it more I'd be having choice words with MG about their choice of "assistance" provider and insisting since it fell under the assistance, it's still on them to fix it. When he did this, all the alerts magically went away. He plugged the pump back into the loom, I pressed the brake and the pump kicked in as it should.
Manually powering the vac pump in fact fixed the problem.
His theory was that the software got into a "chicken and egg" scenario, where either it believed there was a switch problem because there was no vacuum, or the switch was actually stuck because there was no vacuum, and therefore wouldn't start the pump, and the act of forcing the pump fixed the issue. I've emailed my local dealer to see what they say on the matter. But I've experimented (a bit), and driven 35 miles since and no problem reoccurrence. His suggestion is that should it happen next time, tap the vacuum switch (he pointed it out), disconnect and reconnect the pump, and if that doesn't work, call them and try to repeat the fix.
That's my story. I certainly won't be fiddling with the wiring myself, and wouldn't recommend people do so if they experience the same sort of thing. Best to call MG Assistance and let them have a crack at it...
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