Brake failure

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Thekuai

Well-known member
Joined
Oct 12, 2018
Messages
45
Brakes broke?

I Go to start the car, and this happens.
Any ideas?

12v reading 12.7 volts on accessory mode

I have an OBD2 dongle for leafspy plugged in and a fleet karma device plugged in to obd port all the time.



[youtube]https://youtu.be/Ts2fUm8Eme0[/youtube]
 
Try the 12 volt battery voltage with the car off completely for at least 15 minutes.

That Photobucket link started a cascade of popup "traps" in which the only way to escape what appeared to be a scam site was to close my browser.
 
I use a battery tender every time I charge my car. I had just disconnected it before turning on the car in the video from charging overnight
 
Best thoughts:
1) Nissan personally has a bulletin out to not leave devices plugged into the OBDII port for long periods of time "as they cause issues with brakes and other systems”. https://flipthefleet.org/2019/nissan-advise-not-to-use-aftermarket-obd2-devices/
2) Reset the car by removing the Negative terminal from the battery for 15 minutes. Then re-attach it.
3) Clear any and all codes with LeafSpy Pro

I personally leave a https://bafxpro.com/products/obdreader plugged in at all times. However, I modified mine to be powered off accessory power, so it doesn't appear plugged in for a long time--it's only on when the car is on.

If the issue persists after a power cycle, you probably have a failure in the car somewhere.

The only commonality of all of those errors is the "Comm error". This means that your devices are having trouble communicating on the CAN bus. Either some device has gone bad and is putting interference on the bus, or you possibly have a shorted, disconnected, or chewed wire somewhere.

Did you mess with the TCU lately, or have any TCU work done? The TCU is reporting disconnect from the rest of the car. I know when I unplugged one of the connectors on my TCU, I got a similar slew of errors.
 
Lothsahn said:
Best thoughts:
1) Nissan personally has a bulletin out to not leave devices plugged into the OBDII port for long periods of time "as they cause issues with brakes and other systems”. https://flipthefleet.org/2019/nissan-advise-not-to-use-aftermarket-obd2-devices/
2) Reset the car by removing the Positive terminal from the battery for 15 minutes. Then re-attach it.
3) Clear any and all codes with LeafSpy Pro

I personally leave a https://bafxpro.com/products/obdreader plugged in at all times. However, I modified mine to be powered off accessory power, so it doesn't appear plugged in for a long time--it's only on when the car is on.

If the issue persists after a power cycle, you probably have a failure in the car somewhere.

The only commonality of all of those errors is the "Comm error". This means that your devices are having trouble communicating on the CAN bus. Either some device has gone bad and is putting interference on the bus, or you possibly have a shorted, disconnected, or chewed wire somewhere.

Did you mess with the TCU lately, or have any TCU work done? The TCU is reporting disconnect from the rest of the car. I know when I unplugged one of the connectors on my TCU, I got a similar slew of errors.

I'm leaning towards 1) i just read that article. I have a fleet carma and a bluetooth obd2 for leafspy which are connected 24/7 with an obd2 y splitter cable. That probably doubles my odds of failure.

I tried disconnecting 12v and clearing to no avail.

I pulled the radio fuse previously because my nissan connect app wasn't turning on the climate control so maybe that's why?
 
Thekuai said:
Lothsahn said:
Best thoughts:
1) Nissan personally has a bulletin out to not leave devices plugged into the OBDII port for long periods of time "as they cause issues with brakes and other systems”. https://flipthefleet.org/2019/nissan-advise-not-to-use-aftermarket-obd2-devices/
2) Reset the car by removing the Positive terminal from the battery for 15 minutes. Then re-attach it.
3) Clear any and all codes with LeafSpy Pro

I personally leave a https://bafxpro.com/products/obdreader plugged in at all times. However, I modified mine to be powered off accessory power, so it doesn't appear plugged in for a long time--it's only on when the car is on.

If the issue persists after a power cycle, you probably have a failure in the car somewhere.

The only commonality of all of those errors is the "Comm error". This means that your devices are having trouble communicating on the CAN bus. Either some device has gone bad and is putting interference on the bus, or you possibly have a shorted, disconnected, or chewed wire somewhere.

Did you mess with the TCU lately, or have any TCU work done? The TCU is reporting disconnect from the rest of the car. I know when I unplugged one of the connectors on my TCU, I got a similar slew of errors.

I'm leaning towards 1) i just read that article. I have a fleet carma and a bluetooth obd2 for leafspy which are connected 24/7 with an obd2 y splitter cable. That probably doubles my odds of failure.

I tried disconnecting 12v and clearing to no avail.

I pulled the radio fuse previously because my nissan connect app wasn't turning on the climate control so maybe that's why?

If you've already disconnected 12v and cleared and it didn't work, it's probably not your FC or splitter. That said, try plugging JUST the BT ODB2 for Leafspy into the car--no FC box and no splitter cable. See if you can clear that way after disconnecting 12V.

You did disconnect the 12V for 15 minutes, right? Not just a quick unplug, replug job? It does take a few minutes to discharge the capacitors.

If you had this start after you pulled a fuse, I'd try re-inserting the fuse. If you've already done that, go check the fuse and make sure it's not blown. I do know for a fact that the TCU has 3 cables - Power, CAN, and antenna. If you pull power, the TCU won't work, there's a single code, but the car is otherwise fine. If you pull antenna, it throws a different code, but the car is fine. If you pull the CAN connector, you get a ton of CAN bus comm errors.

You might also consider pulling the TCU fuse and leaving it out. If the TCU is messing with the bus, pulling the fuse for it might restore everything. Worth trying... if it does resolve it, you at least know what's causing the problem.

At this point, if you've double checked everything you can do, the only last remaining thing would be to buy a different ODBII connector (I recommend BAFX) and try clearing with that. That's a longshot, but *maybe* your ODBII device is actually causing the problem. I doubt it.

Most likely, your car will need repairs. If the dealer gives you some outrageous number and you're mechanically inclined, grab the service manual and start digging. But this particular project sounds... not fun. :(

Really dumb question--you haven't been in the dash disconnecting or reconnecting any cables, have you? If so, double check all the connections are snug.

If you need my help with suggestions on the service manual, let me know, but I don't know much more than you at this point. This is a failure I haven't seen before.

Sorry for the bad news.
 
Lothsahn said:
Thekuai said:
Lothsahn said:
Best thoughts:
1) Nissan personally has a bulletin out to not leave devices plugged into the OBDII port for long periods of time "as they cause issues with brakes and other systems”. https://flipthefleet.org/2019/nissan-advise-not-to-use-aftermarket-obd2-devices/
2) Reset the car by removing the Positive terminal from the battery for 15 minutes. Then re-attach it.
3) Clear any and all codes with LeafSpy Pro

I personally leave a https://bafxpro.com/products/obdreader plugged in at all times. However, I modified mine to be powered off accessory power, so it doesn't appear plugged in for a long time--it's only on when the car is on.

If the issue persists after a power cycle, you probably have a failure in the car somewhere.

The only commonality of all of those errors is the "Comm error". This means that your devices are having trouble communicating on the CAN bus. Either some device has gone bad and is putting interference on the bus, or you possibly have a shorted, disconnected, or chewed wire somewhere.

Did you mess with the TCU lately, or have any TCU work done? The TCU is reporting disconnect from the rest of the car. I know when I unplugged one of the connectors on my TCU, I got a similar slew of errors.

I'm leaning towards 1) i just read that article. I have a fleet carma and a bluetooth obd2 for leafspy which are connected 24/7 with an obd2 y splitter cable. That probably doubles my odds of failure.

I tried disconnecting 12v and clearing to no avail.

I pulled the radio fuse previously because my nissan connect app wasn't turning on the climate control so maybe that's why?

If you've already disconnected 12v and cleared and it didn't work, it's probably not your FC or splitter. That said, try plugging JUST the BT ODB2 for Leafspy into the car--no FC box and no splitter cable. See if you can clear that way after disconnecting 12V.

I tried just plugging in the BT OBD, no splitter. Everytime I clear a DTC, it comes back when leafspy automatically reads the DTCs after clearing.

You did disconnect the 12V for 15 minutes, right? Not just a quick unplug, replug job? It does take a few minutes to discharge the capacitors.

yes I made sure to wait at least 15 minutes after disconnecting the 12v

If you had this start after you pulled a fuse, I'd try re-inserting the fuse. If you've already done that, go check the fuse and make sure it's not blown. I do know for a fact that the TCU has 3 cables - Power, CAN, and antenna. If you pull power, the TCU won't work, there's a single code, but the car is otherwise fine. If you pull antenna, it throws a different code, but the car is fine. If you pull the CAN connector, you get a ton of CAN bus comm errors.

I pulled the red 10a radio fuse under the hood about 2 weeks prior to this so I don't think that is it. That's the only fuse I pulled.

You might also consider pulling the TCU fuse and leaving it out. If the TCU is messing with the bus, pulling the fuse for it might restore everything. Worth trying... if it does resolve it, you at least know what's causing the problem.

after I cleared the TCU code, it never came back

At this point, if you've double checked everything you can do, the only last remaining thing would be to buy a different ODBII connector (I recommend BAFX) and try clearing with that. That's a longshot, but *maybe* your ODBII device is actually causing the problem. I doubt it.

Most likely, your car will need repairs. If the dealer gives you some outrageous number and you're mechanically inclined, grab the service manual and start digging. But this particular project sounds... not fun. :(

I bought the certified certified preowned 1 year ago and it came with a 2 year warranty

Really dumb question--you haven't been in the dash disconnecting or reconnecting any cables, have you? If so, double check all the connections are snug.

not a dumb question, but no I have not messed with the dash or any cables. In fact the night before I drove 30 miles no problem. Charged it overnight without touching anything else and woke up to this problem about 9 hours after charging completed. I had the battery tender connected up until this point as well.

If you need my help with suggestions on the service manual, let me know, but I don't know much more than you at this point. This is a failure I haven't seen before.
thanks, you are the only one helping really this far, I'm going to the Nissan dealer today. Wish me luck!
Sorry for the bad news.
 
Thekuai said:
I bought the certified certified preowned 1 year ago and it came with a 2 year warranty

Glad to hear it. I realize the other questions were long-shots, but I had to ask. Let us know what the root cause is--it helps us help others!
 
Update:

Local Nissan dealer wants $4600 to replace the brake control unit and abs unit. It is NOT covered under warranty. The warranty I have is a limited certified preowned warranty. The car is a 2015 with 25,000 miles. I called 1877nogasev and they are getting the info from this dealer and will get back to me on monday the latest.
 
I assume that you say it isn't covered under the pre-owned warranty because you read the warranty, and not because the dealership told you that? Is it a Nissan CPO warranty or another plan?
 
Thekuai said:
Update:

Local Nissan dealer wants $4600 to replace the brake control unit and abs unit. It is NOT covered under warranty. The warranty I have is a limited certified preowned warranty. The car is a 2015 with 25,000 miles. I called 1877nogasev and they are getting the info from this dealer and will get back to me on monday the latest.

Oh gosh that's frustrating. I'll send you a PM. Give me a call and I'll see if I can't help.

Sounds like the dealership just wants to start replacing components until they find what works. It's highly unlikely your brake control unit and abs unit both failed.
 
LeftieBiker said:
I assume that you say it isn't covered under the pre-owned warranty because you read the warranty, and not because the dealership told you that? Is it a Nissan CPO warranty or another plan?

Standard warranty covers electrical for 3 years/36k miles. Certified pre-owned warranty specifically excludes electrical and brakes:
http://cpo.nissanusa.com/userdata/11421/files/2017%20cpo%20warrantybooklet.pdf

(see #3 on page 4).

On an ICE, the CPO warranty ONLY covers engine, transmission, and drivetrain. It explicitly excludes:
Any and all electric or hybrid vehicle systems/components, including but
not limited to, high voltage (HV) components (including batteries
and cells), hybrid transmission, powertrain control systems: inverters,
converters, motors, generators, battery chargers, HV PCUs and PCMs;
and regenerative braking systems.


The excluded components are the "engine, transmission, and drivetrain" on a Leaf. Essentially, that warranty on a Leaf is a complete scam. Best I can tell, it covers literally nothing. I'm quite angry at Nissan right now, and it's not even my car.
 
I know about the crappy CPO coverage. I was trying to establish if this was that. There is a much better Nissan aftermarket warranty, called Gold Preferred, IIRC. That may cover non-wear braking system items.
 
LeftieBiker said:
I know about the crappy CPO coverage. I was trying to establish if this was that. There is a much better Nissan aftermarket warranty, called Gold Preferred, IIRC. That may cover non-wear braking system items.

I only have the crappy no cost CPO warranty coverage. It does however have 3 years of roadside and tow assistance and car rental reimbursement as the only benefit for a leaf.

I did not purchase the platinum or gold warranties because the leaf is supposed to be a generally maintenance free reliable car. In hindsight I guess I'm regretting that now. A car with 25k miles should not have brake faults of any kind or repairs costing $4600. That's like engine or transmission replacement for an ICE CAR at 25k miles. Ridiculous!
 
Lothsahn said:
Thekuai said:
Update:

Local Nissan dealer wants $4600 to replace the brake control unit and abs unit. It is NOT covered under warranty. The warranty I have is a limited certified preowned warranty. The car is a 2015 with 25,000 miles. I called 1877nogasev and they are getting the info from this dealer and will get back to me on monday the latest.

Oh gosh that's frustrating. I'll send you a PM. Give me a call and I'll see if I can't help.

Sounds like the dealership just wants to start replacing components until they find what works. It's highly unlikely your brake control unit and abs unit both failed.

Thank you, I'll try to give you a call tomorrow.
 
I had that combination of DTCs happen once in a while on my 2015 and would get strange brake pedal response, but always had brake assist and could always clear the errors (and restore normal brake pedal response) by clearing codes with Leaf Spy, disconnecting/reconnecting 12V battery, and clearing codes again with Leaf Spy. I often had to repeat the process at least twice to get all codes cleared and restore normal operation. The cause was intermittent CAN bus communication errors caused by a glitch in firmware of the intelligent brake controller. It became more frequent as the car got older so I finally had the intelligent brake controller (which includes the master cylinder) replaced under the aftermarket extended warranty. Try clearing codes, disconnecting/reconnecting battery, clearing codes, disconnecting/reconnecting battery, and clearing codes again at least twice before giving up. If you get the codes cleared, the car may be fine for quite a while before it happens again. There are other threads regarding brake pedal response on the forum that discuss this issue.
 
GerryAZ said:
I had that combination of DTCs happen once in a while on my 2015 and would get strange brake pedal response, but always had brake assist and could always clear the errors (and restore normal brake pedal response) by clearing codes with Leaf Spy, disconnecting/reconnecting 12V battery, and clearing codes again with Leaf Spy. I often had to repeat the process at least twice to get all codes cleared and restore normal operation. The cause was intermittent CAN bus communication errors caused by a glitch in firmware of the intelligent brake controller. It became more frequent as the car got older so I finally had the intelligent brake controller (which includes the master cylinder) replaced under the aftermarket extended warranty. Try clearing codes, disconnecting/reconnecting battery, clearing codes, disconnecting/reconnecting battery, and clearing codes again at least twice before giving up. If you get the codes cleared, the car may be fine for quite a while before it happens again. There are other threads regarding brake pedal response on the forum that discuss this issue.

Unfortunately every time I cleared DTC codes, they would reappear as leafspy reads the codes again automatically after clearing them. I cannot try right now as nissan has my car right now and I am waiting to hear back from nissan owner services to see if they can cover some of the cost.
 
I found that it took a combination of clearing codes with Leaf Spy, disconnecting/reconnecting battery, clearing codes with Leaf Spy, and repeating the process at least twice to get all codes cleared. I hope Nissan will cover some of the cost for you because it is a known issue.
 
GerryAZ said:
I found that it took a combination of clearing codes with Leaf Spy, disconnecting/reconnecting battery, clearing codes with Leaf Spy, and repeating the process at least twice to get all codes cleared. I hope Nissan will cover some of the cost for you because it is a known issue.

I hope so. I reached out to fleetcarma as well as it was theur telematic obd2 device that I had left in all the time to participate in their reward program.
 
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