How to get electronic parking brake working after manual release

[GarretD]

Hi Leaf community,
The electronic parking brake in my Nissan Leaf 2011 did not release after replacing my 12v battery. As car could not be towed I had to manually release the parking brake. I could drive it after I had done that but now I have a blinking parking light on the dash (and also, as a result the yellow and red system lights).
Does anybody know how to get the electronic brake working again? I have reset all the DTC"s with Leafspy Pro and am only left with U1000 00C0 EV/HEV CAN Comm Circuit, P31B9 00C0 EV/HEV and U1000 0009 METER CAN Comm Circuit faults. So strangely enough no parking brake DTC fault. The Nissan manual says:
After manual release, perform “EHS/PKB” self diagnosis. When a malfunction is detected, erase self diagnosis result for “EHS/PKB”.

Went to mechanic and they said they couldn't access the EHS system. They wanted the car for a day to try to fix the problem but I am afraid I will end up with a big bill and no solution.

Because of the DTC's I'm wondering what the real issue is here. Any help appreciated.

 

[Stanton]

Was there some problem/reason you replaced the 12v battery (other than it being flat-out dead)? I'm thinking there may have been some collateral damage around why you replaced the 12v, since those error codes indicate something wrong with the CAN bus communication.
For the record, did you disconnect the 12v for a bit--as opposed to just clearing codes with LeafSpy?

 

[GarretD]

Thanks for your reply, Stanton.
I had to replace the 12v battery as it was getting bad and I often had to put it on a charger. While changing the 12v battery I managed to get the 250a blown which sits in the positive terminal block. So had to replace that terminal block with a second hand one (was easier that finding a 250a fuse which would fit). This probably indicates a power surge which might have fried some other systems.
Is there a way to replace the CAN bus communication?

 

[GerryAZ]

Try clearing DTC's, disconnect 12V battery, connect 12V light bulb or resistor between positive and negative cable terminals to discharge power supplies in control modules (keep bulb or resistor connected for a few minutes), reconnect 12V battery, clear DTC's again. Repeat this process a couple more times if any DTC's remain. If you are unable to clear the CAN Bus communication errors through this process, then it is likely that one or more control modules have been damaged. Please note it is not unusual to have CAN Bus communication errors caused by low voltage from a weak or discharged 12V battery, but this procedure should clear them.

 

[Stanton]

While changing the 12v battery I managed to get the 250a blown which sits in the positive terminal block.

This is why I'm not a fan of battery maintainers to trickle charge the 12v battery--which are pushed a lot on this forum. I acknowledge there are reasons for "dead" 12v batteries in Leafs (ghost loads due to comm circuits, inadequate 12v charging algorithm), but the solution is buy a better 12v (like Lithium) or at least replace it regularly--not battery maintainers.
Unfortunately, as pointed out, there may have been some collateral damage.

 

[GarretD]

Try clearing DTC's, disconnect 12V battery, connect 12V light bulb or resistor between positive and negative cable terminals to discharge power supplies in control modules (keep bulb or resistor connected for a few minutes), reconnect 12V battery, clear DTC's again. Repeat this process a couple more times if any DTC's remain. If you are unable to clear the CAN Bus communication errors through this process, then it is likely that one or more control modules have been damaged. Please note it is not unusual to have CAN Bus communication errors caused by low voltage from a weak or discharged 12V battery, but this procedure should clear them.

Thanks Gerry. Tried your suggestions a couple of times but no change in DTC. So one or more control modules must be damaged.
Do you know where can I find these control modules and how can I deduce which one's are broken?

 

[LeftieBiker]

While changing the 12v battery I managed to get the 250a blown which sits in the positive terminal block.

This is why I'm not a fan of battery maintainers to trickle charge the 12v battery--which are pushed a lot on this forum. I acknowledge there are reasons for "dead" 12v batteries in Leafs (ghost loads due to comm circuits, inadequate 12v charging algorithm), but the solution is buy a better 12v (like Lithium) or at least replace it regularly--not battery maintainers.
Unfortunately, as pointed out, there may have been some collateral damage.

There are some situations in which just having a better battery isn't going to keep it alive. And in a decade here, this is the first mention I've seen of serious damage being done by the installation (or attempted installation) of a battery maintainer. I do recommend replacing the FLA battery with an AGM, but not always as the first step.

 

[GerryAZ]

If the error codes remain the same, then you need to look at the METER and EV/HEV modules (or the modules they communicate with). I know that statement is not very helpful, but the systems in the car are so intertwined that it will likely be very hard to find/fix. The meter module controls the display in front of the steering wheel and the EV/HEV module monitors/controls some of the EV systems (I am not sure what all it controls). I was concerned that there could be additional damage/issues from the blown fuse and am surprised the car can be driven in that condition. The only things I can think of that would blow that fuse are shorting positive to ground or connecting the battery backwards--either one has the possibility of doing a lot of damage (even on a conventional car). There are a bunch of small fuses in several locations in the car (fuse panels in/under dash and on the bottom side of the power distribution modules--located under the hood, one on each front fender; those need to be taken loose and raised to see the fuses on the underside).

 

[GarretD]

Thanks for you explanation Gerry. Will have a look at those fuses and might have to look into those modules you mentioned but for now I concentrated on error P31B9 and this is what I found in the Nissan Factory Service manuals:

https://ibb.co/nMkySTg

According to that the error is in parking brake control module or VCM. I have started by extracting the parking brake control module but how do I test if it is faulty? Any electrical wizards here? This is the electrical diagram of the module

https://ibb.co/mR2shvy

So anybody have an idea how to test with a multimeter (and a sprae 12v battery) if the module is still okay? And is there a way to reset it or should this already have been done by clearing the DTCs?

 

[GerryAZ]

Notice the CAN-H and CAN-L wires! That is the two-wire CAN Bus that networks all of the control modules together--a parallel connection with wires running throughout the car. A problem with any module (or the wires) can cause CAN Bus communication errors and be difficult to troubleshoot. It appears you have access to the factory service manual so I hope there are some troubleshooting hints in the parking brake section.