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Discussion Starter · #1 ·
Hello all, I am hoping someone one can help me diagnosis an issue with a miles Zx40s. The car has been occasionally going into a sort of limp mode where top speed is 9mph. Occasionally I would get a code 43 on the controller, I believe I fixed that by limiting the voltage of the cars auxillary 12v. Despite all that the car seems to still be limited to 9mph even with the wheels off the ground.

Any help would be appreciated.
 

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I would test your batteries and clean the cables.

coorosion on ground wires both under the hood and around the steering column are common.

issues with the contactors under the hood are also common

good Luck lots of places to check and cleanup.
 

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Discussion Starter · #3 ·
Batteries are tested, I charged them all independently and reinstalled them. Terminals are clean. I will go through the grounds but I don't think that's the problem. The power is there, when WOT is applied the car will spin tires on gravel then after 1 second it derates it. I see the same thing when the driver tires are lifted, it will hit 16 mph then fall back to 9mph. I've checked the photo tachometer for debris.

I'm thinking it's part of the braking system or the TPS
 

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It might be as simple as the throttle

do you have an AC car or an older DC?

Mine (48v) did not have TPS, ECU or any electronic controls everything was manually hardwired, when things didn’t work it was due to a bad connection or coorsion between the contactors/controller and something in the cab.

my throttle for example has 12v going through it, when the connection between it and the harness became intermittent it looked like low voltage (not 12 volt) so I barely got any power.
Eventually it wouldn’t even signal the contactors to close.

When my brushes went (was a bad spring retainer in the motor)
Likewise I got a lot of hopping and minimal power.

You have to start plugging around with a voltmeter, etc to find the fault but I bet your controller isn’t getting a clean signal from inside the cab.
 

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Discussion Starter · #5 ·
It's a 72v. Unfortunately I think a few people have gone through the electronics, so I'm not sure what's original and what's been modified.
 

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Discussion Starter · #6 ·
I bet you are right though. The issue is so specific I figured someone would recognize the symptoms.
 
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