P0A43 resolver open/short circuit
- Thread starter martig
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The gray connector is on the end of the motor on the right hand side of the car. There is a small tab up near where the wires enter the connector that must be squeezed near the wires to lever a plastic arm away from the locking nub, and the connector has to be pulled upward at the same time.
Hi,
Thank you for the advice. I managed to open the connector and measure the resistances of the resolver coils. Fortunately they were all within spec. I discovered that one of the contacts was terribly corroded. I had to use a 0.4 mm drill bit to clean it out. Now there are no resolver/motor speed related DTCs. But when I put the car to drive it seems it wants to move a bit and the motor also makes some high pitched sound for a second and then stops and gives me a P1A29 DTC / motor overcurrent.
I already checked the the battery voltage - it is always around 12.x and when ready it jumps to 14.4 V. I also checked the motor speed. It shows the speed as -9976 RPM when the car is standing still. Is this correct or do I still need to work on those resolver connector contacts?
Thank you for the advice. I managed to open the connector and measure the resistances of the resolver coils. Fortunately they were all within spec. I discovered that one of the contacts was terribly corroded. I had to use a 0.4 mm drill bit to clean it out. Now there are no resolver/motor speed related DTCs. But when I put the car to drive it seems it wants to move a bit and the motor also makes some high pitched sound for a second and then stops and gives me a P1A29 DTC / motor overcurrent.
I already checked the the battery voltage - it is always around 12.x and when ready it jumps to 14.4 V. I also checked the motor speed. It shows the speed as -9976 RPM when the car is standing still. Is this correct or do I still need to work on those resolver connector contacts?
Bad connections due to the corrosion could definitely be causing signal issues. This could manifest as missing counts of the encoder such that it gives a speed error.
i'm not familiar with contact cleaning using a drill bit; if it is blue or green corrosion, then the easiest way is to soak it in vinegar which will loosen up and dissolve most of it, and a soft bristle brush (toothbrush) can be used to clean the rest.
If it is rusty corrosion, then vinegar will also work but may take repeated cleanings; Also some light oil can help loosen up the rust and it can be scrubbed and brushed out, then clean with soap and water to get rid of the oil, and dry it well.
Inspect the end of the motor for corrosion also, such as from road salt, etc. There is likely more places affected since you found it in the connector.
i'm not familiar with contact cleaning using a drill bit; if it is blue or green corrosion, then the easiest way is to soak it in vinegar which will loosen up and dissolve most of it, and a soft bristle brush (toothbrush) can be used to clean the rest.
If it is rusty corrosion, then vinegar will also work but may take repeated cleanings; Also some light oil can help loosen up the rust and it can be scrubbed and brushed out, then clean with soap and water to get rid of the oil, and dry it well.
Inspect the end of the motor for corrosion also, such as from road salt, etc. There is likely more places affected since you found it in the connector.
One of the pins on the female connector was really packed with green corrosion. Couldn’t really even insert anything. I used a drill bit that went into the other pins without effort.
I tried leaving it in vinegar for half an hour, but it didn’t really work. I will try again today.
The interesting thing is that it’s not giving the motor speed codes anymore. I hope that the MCU is ok. I haven’t taken the cover off yet.
I tried leaving it in vinegar for half an hour, but it didn’t really work. I will try again today.
The interesting thing is that it’s not giving the motor speed codes anymore. I hope that the MCU is ok. I haven’t taken the cover off yet.
I managed to get the car running for a moment by sticking some thin wire into the corroded pin. This didn’t last for very long. I think I need a new 14 pin female connector. Do you have any idea where I could get one?
The other option would be removing the connector and soldering the wires together, but I would rather not go this way if possible.
The other option would be removing the connector and soldering the wires together, but I would rather not go this way if possible.
That's a good catch to find that connector, i checked my MCU and it looks like the same 13-pin connector. There is a rubber gland that is supposed to seal and keep out water. There is also a tool that can release the terminal and allow it to be extracted.
Which color wire or pin number was the culprit? a temporary jumper wire could probably be rigged to bypass the connector for that wire just for testing, verification and get the car driving again until you can get a new terminal.
Which color wire or pin number was the culprit? a temporary jumper wire could probably be rigged to bypass the connector for that wire just for testing, verification and get the car driving again until you can get a new terminal.
Hi,
I think it was pin 13. The effect is that it's showing the RPM as -4xxx when the car is not moving.
I managed to get the car running for a while until I decided to open up the connector again. Bad idea, couldn't get it working afterwards.
Anyway, now my plan is to replace the connector. So I'll need to take off the MCU, cut the old connector off and crimp on new contacts. I would've liked to avoid this, but I see no other option now. The contact is probably not gonna come out because I stuck some wire strands into it and finally I managed to break the drill bit into it.
Not a a big problem altogether. I'm not in a hurry. I have already ordered the new connector.
While I'm taking off the MCU should I also check or even preventively replace some components? I've read about the MCU fuse.
I think it was pin 13. The effect is that it's showing the RPM as -4xxx when the car is not moving.
I managed to get the car running for a while until I decided to open up the connector again. Bad idea, couldn't get it working afterwards.
Anyway, now my plan is to replace the connector. So I'll need to take off the MCU, cut the old connector off and crimp on new contacts. I would've liked to avoid this, but I see no other option now. The contact is probably not gonna come out because I stuck some wire strands into it and finally I managed to break the drill bit into it.
Not a a big problem altogether. I'm not in a hurry. I have already ordered the new connector.
While I'm taking off the MCU should I also check or even preventively replace some components? I've read about the MCU fuse.
eldenh
Well-known member
The fuse under the MCU cover is there to protect the wires to the OBC and is very unlikely to fail until something in the OBC does.
kiev said:
The best treatment is washing with baking soda mix first (this will remove most of the corrosion very quickly) before pickling with vinegar (or better: citric acid) and then another baking soda rinse to neutralise and water to rinse off, followed by 95%isopropyl alcohol to dry the whole thing out before reassembly
I'd advise packing the connector with grease when reassembling. Water obviously got in and it can't get in if there's already dielectic grease in the spaces
Baking soda paste is the "go to" treatment for most battery leakage (acid or alkaline or lithium) or copper corrosion before taking any further steps. It's cheap, it's safe, it works and it's usually the manufacturer recommended treatment to neutralise things.
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