Brake failure

[Lothsahn]

Here's some more information about that failure:
https://flipthefleet.org/2018/leaf-brakes-failures/

https://flipthefleet.org/wp-content/uploads/2018/11/MY2013-2015-Leaf-Brake-Issue_R.pdf

There's a firmware update to fix the issue. Unfortunately, if your brake controller won't recover, it may be impossible to update the firmware to resolve this.

Btw, I had problems as well getting the LeafSpy image to load. For people having problems loading the image, here's a direct link to the image: https://i135.photobucket.com/albums/q129/thekuai/Mobile%20Uploads/Screenshot_20191111-170124_LeafSpy%20Pro.jpg

 

[Lothsahn]

Based on the diagnostic codes, I have concerns with the diagnostic that the ABS & BCM are actually the problem.

For just the CAN comm errors, we have a few categories of diagnostic codes:
1) Brakes CAN
2) Charger CAN
3) EV/HEV CAN
4) HVAC CAN
5) HV Battery CAN
6) Multi AV CAN
7) TCU CAN

This page has information about the leaf CAN busses: https://www.mynissanleaf.com/viewtopic.php?t=4131

There are 3 CAN busses in the Leaf. There's the primary bus (most of the car is on this), the EV bus (the battery, charger, and TCU), and the AV bus (not relevant here).

Given we have failures across two busses, that's concerning. I don't know how a failed Brake module could cause failures on the EV bus.

There is one component that's on both busses, as described in that page: The VCM. It's also possible that rodents got into the car and chewed a number of wires, causing multiple failures at once.

I could be wrong. I'm not a Leaf certified tech or mechanic, but the idea that a BCM and ABS problem caused CAN issues with the battery, charger, and TCU seems strange to me. *maybe* if the BCM locks up, the VCM doesn't even try talking to those components? I just don't know. Can anyone post LeafSpy snapshots of other people with intelligent brake controller failures?

 

[Thekuai]

Based on the diagnostic codes, I have concerns with the diagnostic that the ABS & BCM are actually the problem.

For just the CAN comm errors, we have a few categories of diagnostic codes:
1) Brakes CAN
2) Charger CAN
3) EV/HEV CAN
4) HVAC CAN
5) HV Battery CAN
6) Multi AV CAN
7) TCU CAN

This page has information about the leaf CAN busses: https://www.mynissanleaf.com/viewtopic.php?t=4131

There are 3 CAN busses in the Leaf. There's the primary bus (most of the car is on this), the EV bus (the battery, charger, and TCU), and the AV bus (not relevant here).

Given we have failures across two busses, that's concerning. I don't know how a failed Brake module could cause failures on the EV bus.

There is one component that's on both busses, as described in that page: The VCM. It's also possible that rodents got into the car and chewed a number of wires, causing multiple failures at once.

I could be wrong. I'm not a Leaf certified tech or mechanic, but the idea that a BCM and ABS problem caused CAN issues with the battery, charger, and TCU seems strange to me. *maybe* if the BCM locks up, the VCM doesn't even try talking to those components? I just don't know. Can anyone post LeafSpy snapshots of other people with intelligent brake controller failures?

TCU must have been an old code from when I pulled the radio fuse to fix carwings. After clearing everything here are the only faults:

 

[Lothsahn]

Based on the diagnostic codes, I have concerns with the diagnostic that the ABS & BCM are actually the problem.

For just the CAN comm errors, we have a few categories of diagnostic codes:
1) Brakes CAN
2) Charger CAN
3) EV/HEV CAN
4) HVAC CAN
5) HV Battery CAN
6) Multi AV CAN
7) TCU CAN

This page has information about the leaf CAN busses: https://www.mynissanleaf.com/viewtopic.php?t=4131

There are 3 CAN busses in the Leaf. There's the primary bus (most of the car is on this), the EV bus (the battery, charger, and TCU), and the AV bus (not relevant here).

Given we have failures across two busses, that's concerning. I don't know how a failed Brake module could cause failures on the EV bus.

There is one component that's on both busses, as described in that page: The VCM. It's also possible that rodents got into the car and chewed a number of wires, causing multiple failures at once.

I could be wrong. I'm not a Leaf certified tech or mechanic, but the idea that a BCM and ABS problem caused CAN issues with the battery, charger, and TCU seems strange to me. *maybe* if the BCM locks up, the VCM doesn't even try talking to those components? I just don't know. Can anyone post LeafSpy snapshots of other people with intelligent brake controller failures?

TCU must have been an old code from when I pulled the radio fuse to fix carwings. After clearing everything here are the only faults:

That's better. The EV fault is still additional, but maybe that's because the car refuses to go into drive mode.

Any chance you can pull firmware revisions via LeafSpy? It'd be good to know the FW of the Brake controller. Firmware is in the same service menu as the DTC's.

Also, after you do that, disconnect the 12V battery, put it on a maintainer, and leave the power off to the car for quite a while (longer than the 15 minutes before). Some people have reported that an extended power outage managed to finally reset the brake controller, at least temporarily.

 

[Thekuai]

Unfortunately the car is at Nissan currently waiting to see if 877nogasev will cover some of the out of warranty repair costs. It's a 3 business day case by case review process.

Seems like my brake controller is not even showing up on the version page. I did take a picture of unit's default firmware stamp. The dealer said there is no history of the voluntary brake firmware recall being done.

The car does go into ready mode, I drove it to the dealer!, carefully.

 

[Lothsahn]

Yes, the brake controller is missing. I can confirm mine says 3NA0A BRAKE as the top line.

The brake module for your car is $1600 brand new:
https://www.nissanpartsdeal.com/parts/nissan-control-asmy-br~46007-3nf5a.html

Perhaps you could get one from a wrecked Leaf and have them install it, or install it yourself. Then immediately go have the firmware update (voluntary recall) installed.

You want to make sure that the exact part number matches (3NF5A), as there have been different revisions of the brake controller.

I bet the $4600 they quoted you was to replace both the ABS and BCM. In reality, I bet only the BCM is failed.

 

[Thekuai]

Yes, the brake controller is missing. I can confirm mine says 3NA0A BRAKE as the top line.

The brake module for your car is $1600 brand new:
https://www.nissanpartsdeal.com/parts/nissan-control-asmy-br~46007-3nf5a.html

Perhaps you could get one from a wrecked Leaf and have them install it, or install it yourself. Then immediately go have the firmware update (voluntary recall) installed.

You want to make sure that the exact part number matches (3NF5A), as there have been different revisions of the brake controller.

I bet the $4600 they quoted you was to replace both the ABS and BCM. In reality, I bet only the BCM is failed.

Out of curiosity would a newer one work? 2016 and up dont seem to be affected because they come with a newer brake firmware correct?

It even says that part was replaced by 46007-4NP3E on that parts page

 

[nlspace]

Those previous errors are for the CAN buss, not the Brake Controller or Actuator. It seems that many times multiple CAN errors can be caused by a weak, old or worn out 12V Aux battery. There is a test procedure for the 12V in the FSM and it has been posted on this forum, but a search for 12V battery will not find anything.

Serious Error in previous advice:
DO NOT REMOVE THE POSITIVE CABLE FIRST! This is a massive safety hazard. In all cars the negative terminal must be removed first to avoid arcing and welding of tools. If you touch the car chassis with a wrench while disconnecting the positive terminal first, you willhave lots of sparks and arcs and possibly fire and weld that wrench in place.

The correct procedure (while not connected to EVSE) is to push the start button to accessory mode, On->Off, then get out and shut the car doors and wait 5 minutes, then disconnect the negative terminal. After that it is safe to remove the positive terminal. Wait 10-15 minutes and reinstall the + terminal first, then the negative.

Don't know where anyone came up with just removing the positive terminal, but that is BAD advice, and not supported by anything in the FSM or safe battery practices.

P3195 is a CAN communication error from the intelligent brake unit. The diagnostic steps include a step to perform self diagnostic and verify that the VCM has No Other ECUs have errors, but that is obviously not true in your case. The service dude appears to have skipped over that step to the final result which says to replace the brake unit.

from page EVC-51:

 

[Lothsahn]

Serious Error in previous advice:
DO NOT REMOVE THE POSITIVE CABLE FIRST! This is a massive safety hazard. In all cars the negative terminal must be removed first to avoid arcing and welding of tools. If you touch the car chassis with a wrench while disconnecting the positive terminal first, you willhave lots of sparks and arcs and possibly fire and weld that wrench in place.

Whoops, my bad. You are correct and I knew better. Remove negative first, connect positive first. I edited my earlier post in case anyone searches and sees it. Others may wish to do the same with the quotation.

That said, I've never had to do the on-off-on thing. If the car was off, disconnecting the battery for 15 minutes was perfectly sufficient.

I don't know that it's fair to say he skipped over that step. We know the output of the diagnostic codes for Leafspy. I have no idea what specific codes Consult threw when doing a self test of the VCM.

That said, it is entirely possible that the error is the VCM. Without replacing parts, we have no way of knowing.

 

[Thekuai]

Those previous errors are for the CAN buss, not the Brake Controller or Actuator. It seems that many times multiple CAN errors can be caused by a weak, old or worn out 12V Aux battery. There is a test procedure for the 12V in the FSM and it has been posted on this forum, but a search for 12V battery will not find anything.

the car was on a 12v desulphating trickle charger all night and every night up until the car was started

Serious Error in previous advice:
DO NOT REMOVE THE POSITIVE CABLE FIRST! This is a massive safety hazard. In all cars the negative terminal must be removed first to avoid arcing and welding of tools. If you touch the car chassis with a wrench while disconnecting the positive terminal first, you willhave lots of sparks and arcs and possibly fire and weld that wrench in place.

I always though just removing the negative terminal was enough to reset? Is it really necessary to remove positive as well?

The correct procedure (while not connected to EVSE) is to push the start button, On->Off->On, then get out and shut the car doors and wait 5 minutes, then disconnect the negative terminal. After that it is safe to remove the positive terminal. Wait 10-15 minutes and reinstall the + terminal first, then the negative.

what exactly is the significance of the on off on? Is it to prep computers for power failure?

Don't know where anyone came up with just removing the positive terminal, but that is BAD advice, and not supported by anything in the FSM or safe battery practices.

P3195 is a CAN communication error from the intelligent brake unit. The diagnostic steps include a step to perform self diagnostic and verify that the VCM has No Other ECUs have errors, but that is obviously not true in your case. The service dude appears to have skipped over that step to the final result which says to replace the brake unit.

so if other ecus have errors then what? Vcm is the culprit? This seems like a telltale sign of the intelligent brake control unit failure as noted on:

https://flipthefleet.org/2018/leaf-brakes-failures/

https://flipthefleet.org/2018/update-17-dec-2018-leaf-brake-faults/

https://flipthefleet.org/2019/nissan-advise-not-to-use-aftermarket-obd2-devices/

 

[nlspace]

The {edit}OFF-ON-OFF{edit} sequence of the start button is found in the FSM. The note says that ECUs may remain powered for up to 5 minutes after OFF. The sequence puts the car in a known state for starting the 5 minute delay.

i have had to remove both the negative and positive terminals in order to perform a car reset. Until that was done i continued to have DTC and spurious errors. i had a car towed to the dealer with a bad 12V, for which they didn't test properly, and they declared the pack dead based upon the DTCs.

i have found wildly varying voltage of cheap 12V trickle desulfators, and in one case (HF 64284) it was running at 14.7 and acid was spitting out the vents. So trust but verify the voltage is my SOP now. Check the water level and specific gravity, and load test your 12V battery to ensure it is really okay.

The Nissan 12V from above was only 17 months old and seemed to be okay by all accounts, except it failed the specific gravity test after a full charge, so it really wasn't charging properly (likely internal short or defect).


Remove any OBDII dongles, make sure the 12V is verified good, then give a try at a proper reset. See if the car starts and drives okay and charges okay. See if the dash shows any MILs or error indicators.

only then use the obd tool. Real CAN communication errors are rare, but the OBD tool could be causing the problems, since it is trying to insert commands on the CAN buss. i consider the OBD dongles and spy app to be unverified tools--it's nice if they work but the code has never been independently checked and verified.

 

[Thekuai]

The ON-OFF-ON sequence of the start button is found in the FSM. The note says that ECUs may remain powered for up to 5 minutes after OFF. The sequence puts the car in a known state for starting the 5 minute delay.

i have had to remove both the negative and positive terminals in order to perform a car reset. Until that was done i continued to have DTC and spurious errors. i had a car towed to the dealer with a bad 12V, for which they didn't test properly, and they declared the pack dead based upon the DTCs.

i have found wildly varying voltage of cheap 12V trickle desulfators, and in one case (HF 64284) it was running at 14.7 and acid was spitting out the vents. So trust but verify the voltage is my SOP now. Check the water level and specific gravity, and load test your 12V battery to ensure it is really okay.

The Nissan 12V from above was only 17 months old and seemed to be okay by all accounts, except it failed the specific gravity test after a full charge, so it really wasn't charging properly (likely internal short or defect).


Remove any OBDII dongles, make sure the 12V is verified good, then give a try at a proper reset. See if the car starts and drives okay and charges okay. See if the dash shows any MILs or error indicators.

only then use the obd tool. Real CAN communication errors are rare, but the OBD tool could be causing the problems, since it is trying to insert commands on the CAN buss. i consider the OBD dongles and spy app to be unverified tools--it's nice if they work but the code has never been independently checked and verified.

Thank you, I will try this if the repair is not covered. From what i read even if the codes are cleared and car returns to normal operation it can still happen again in the future?. So if I can get free new parts, why not? Seems I accelerated the fault by having both a fleetcarma and obd2 bluetooth connected 24/7 with an obd2 y splitter cable. So shame on me. It did work fine for over a year. The Funny thing is I did come across the obd2 device and brake warning article a few months back but I ignored it because I had that bulletproof feeling since it was working fine for so long. Ignorance is bliss till it bites you in the ass I guess.

 

[Thekuai]

The correct procedure (while not connected to EVSE) is to push the start button, On->Off->On, then get out and shut the car doors and wait 5 minutes, then disconnect the negative terminal. After that it is safe to remove the positive terminal. Wait 10-15 minutes and reinstall the + terminal first, then the negative.

so press the brake while pushing start to get into ready mode, turn off, then press brake again and start to wind up in ready mode finally?

Or do not use brakes and go into accessory, on, then off mode finally?

 

[nlspace]

Or do not use brakes and go into accessory, on, then off mode finally?

Go to accessory mode, then OFF. i transposed the instructions while typing them earlier. Sorry for the confusion.

 

[Thekuai]

Those previous errors are for the CAN buss, not the Brake Controller or Actuator. It seems that many times multiple CAN errors can be caused by a weak, old or worn out 12V Aux battery. There is a test procedure for the 12V in the FSM and it has been posted on this forum, but a search for 12V battery will not find anything.

So in theory replacing the brake controller and abs unit may not fix it if it is a can issue. Perhaps while the battery is disconnected while the parts are being replaced will be long enough to clear the bus problems...

 

[nlspace]

Yes if you are getting parts replaced for free, then it is all on them. Hopefully they disconnect the 12V fully during the replacement and that should clear the spurious CAN errors.

There is another thread where DCQC issues were occuring in addition to brake errors. A new 12V solved the problem in that thread. His was only reading 11V, so a totally bad aux battery was root culprit.

 

[Lothsahn]

If he's been properly maintaining his battery and it's reading 12.7v on a multi-meter after being disconnected from the charger for an hour, it's highly unlikely that low voltage is the cause of these errors.

Trying the reset as recommended is a good idea. If the car does begin to function again, take it to the dealer immediately and have the voluntary brake recall done. Once the firmware is updated, the issue should no longer occur. If you don't get the firmware updated, yes, it can occur again.

Those previous errors are for the CAN buss, not the Brake Controller or Actuator. It seems that many times multiple CAN errors can be caused by a weak, old or worn out 12V Aux battery. There is a test procedure for the 12V in the FSM and it has been posted on this forum, but a search for 12V battery will not find anything.

So in theory replacing the brake controller and abs unit may not fix it if it is a can issue. Perhaps while the battery is disconnected while the parts are being replaced will be long enough to clear the bus problems...

Yes, if you have a true issue with the CAN bus (broken/shorted wires, etc), then replacing the brake controller won't fix it. However, it's very possible the CAN bus errors are caused by the malfunctioning brake controller. Remember, this is very likely a device attached to the CAN bus that has a corrupted firmware causing erratic behavior.

I also don't believe you should replace the ABS unit. I believe the entire failure is in the brake controller or VCM, and replacing the broken part will magically "fix" the ABS unit when the CAN issues are corrected.

I still encourage you to give me a call so I can answer any questions you may have in real time. There are also options to fix your car far cheaper than the $4600 quoted.

 

[GerryAZ]

A failure of one module connected to the CAN bus can (and usually does) cause errors in multiple modules. If a module that connects to more than one CAN bus (such as the ABS or VCM) has communication errors, it can cause errors on all of the busses to which it is connected. There are likely no problems with the ABS, VCM, or any other modules besides the intelligent brake controller. That long list of error codes is typical for what I saw whenever my original brake controller caused glitches. Also, I am fairly certain that my original brake controller had the recall firmware update long before the first time it caused glitches.

As a reminder, it may take several sessions of clearing error codes and disconnecting/reconnecting 12V battery (negative terminal only) to get all modules reset and all errors cleared.

 

[Thekuai]

 

[cwerdna]

^^^
Holy crap! Yow! Sorry, I haven't been following this thread, but if my Leaf suffered this issue, I'd be personally trying to part it out/sell as is given its low value.

As I've mentioned numerous times, I put my '13 Leaf SV w/premium up for sale at work (11 bars, SOH between 81 to 83%, built 5/2013 about 66.5K miles now) and lowered the price to $6200 awhile ago. The interest has been virtually nil. So given that I have a perfectly functional Bolt, there's no way I'd blow $5K on a repair.

Let's just hope that this issue makes it eventually to https://www.nissanassist.com/ and they reimburse you.