Will not turn off, various DTCs, I-key system error, parking brake error

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PaulNewall

Member
Joined
Dec 31, 2023
Messages
13
I think (and hope) I am at the end of a long diagnosis and fix saga.
The original problem was that at the end of a trip the car would not properly turn off. The instrument panel displayed messages "I-key system error" and "When parked apply parking brake" (when the brake was on). The only way to get the car to turn off was to disconnect the 12V battery. When the 12V was reconnected the car would not turn on properly. There were a lot of DTCs relating to: IGN relay on stuck, Brake control system, Vehicle speed sensor, SHIFT CAN Comm circuit.
I did not realise it at the time, but this happened generally when it had been raining. Not every time it rained though.
After some time parked, sometimes up to 2 weeks, the car would start working normally again.

I was suspecting the 12V battery, but got the same problem with a new battery, and I spent time looking for CAN bus problems but could not find any.
After a few incidents like this, I eventually paid Nissan for a diagnosis, which was that there was a water leak, probably at the windscreen, and the water was getting into the BMS (Body management controller). They said they has seen a few cases like this.
Since Nissan wanted several thousand pounds to fix it I took the car away. They would replace the BMS and the wiring harness - expensive parts and lots of labour.

Sometimes when it rained, I could feel water on top of the BMS.
I found a gap in the windscreen adhesive about 150mm up from the lower left corner of the windscreen, which I could seal by injecting some adhesive from inside the car.
I found no sign of water damage inside the BMS, but there was a lot of corrosion on one of the connectors, the signal connector that is nearest the top when the BMS is mounted in the car (behind the glove box). This connector has signals for: The key antennae inside the car, the shift, the IGN relays, the power on/off switch. These signals match well with the original symptoms and DTCs.
I guess that when the corrosion was wet it would short some of the contacts.
I cleaned the connector pins on the BMS and socket contacts on the harness, using contact cleaner and a interdental brush to get inside the sockets.
Now I have had 8 weeks without the problem occurring. So I am hoping it's permanently fixed. I will be nervous when driving in the rain for a long time to come.
 
This used to happen to VW Rabbit/Jetta in the 70's and 80's. :rolleyes:

Good to hear you got it sorted on your own. Even if you get the windshield professionally resealed, it will still be cheaper than the stealership.
 
I think (and hope) I am at the end of a long diagnosis and fix saga.
The original problem was that at the end of a trip the car would not properly turn off. The instrument panel displayed messages "I-key system error" and "When parked apply parking brake" (when the brake was on). The only way to get the car to turn off was to disconnect the 12V battery. When the 12V was reconnected the car would not turn on properly. There were a lot of DTCs relating to: IGN relay on stuck, Brake control system, Vehicle speed sensor, SHIFT CAN Comm circuit.
I did not realise it at the time, but this happened generally when it had been raining. Not every time it rained though.
After some time parked, sometimes up to 2 weeks, the car would start working normally again.

I was suspecting the 12V battery, but got the same problem with a new battery, and I spent time looking for CAN bus problems but could not find any.
After a few incidents like this, I eventually paid Nissan for a diagnosis, which was that there was a water leak, probably at the windscreen, and the water was getting into the BMS (Body management controller). They said they has seen a few cases like this.
Since Nissan wanted several thousand pounds to fix it I took the car away. They would replace the BMS and the wiring harness - expensive parts and lots of labour.

Sometimes when it rained, I could feel water on top of the BMS.
I found a gap in the windscreen adhesive about 150mm up from the lower left corner of the windscreen, which I could seal by injecting some adhesive from inside the car.
I found no sign of water damage inside the BMS, but there was a lot of corrosion on one of the connectors, the signal connector that is nearest the top when the BMS is mounted in the car (behind the glove box). This connector has signals for: The key antennae inside the car, the shift, the IGN relays, the power on/off switch. These signals match well with the original symptoms and DTCs.
I guess that when the corrosion was wet it would short some of the contacts.
I cleaned the connector pins on the BMS and socket contacts on the harness, using contact cleaner and a interdental brush to get inside the sockets.
Now I have had 8 weeks without the problem occurring. So I am hoping bms it's permanently fixed. I will be nervous when driving in the rain for a long time to come.
Hi, I am having the same problem. Hoping your fix will work. How do you get to the BMS? Under the hood or have to remove glove box? thanks!
 
Hi, I am having the same problem. Hoping your fix will work. How do you get to the BMS? Under the hood or have to remove glove box? thanks!
It is behind the glovebox. You have to remove about 8 screws to get the glovebox out. Then be careful not to damage the wires going to the glovebox light and the airbag switch in the glovebox.
 
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