Author Topic: Fault Code: Knock sensor 1, circuit A, short circuit to ground  (Read 4788 times)

salamonnandor

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Hello Everyone!

So I boght an 2023 F850GS ADV. I rolled out off BMW and after 100 km I got a 0x3A1B81 fault code it's a Knock sensore problem.
I go back the shop and they search the bike for problem. The cables are fine, the sensore had replaced. I was happy... for 100 km. The problem came back. They sad I have to wait for the new software and I should live with it. I'm now a little fustrated. It's a new bike.. Anyone have a toughts what shod be the problem, or what should I check? I don't want to damage the bike!

Thanks!
Nandi

WayneC

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #1 on: April 23, 2023, 02:21:45 AM »
Interesting to say the least, it would be worth posting an autoscan

Short to earth suggests knock sensor is lower in impedance than the firmware expects hence the error

I would be tempted to hand the bike back to the dealer & lodge a complaint with BMW

Jughead

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #2 on: April 23, 2023, 12:55:21 PM »
Yes, take the bike back and make it their problem.

I would insist on either another new bike completely or a full refund.  If the bike is financed, lodge a complaint with the finance house if the don't come to the party.

salamonnandor

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #3 on: April 24, 2023, 01:34:17 PM »
So yes I send it back to solve the problem. I will post the result.

Mikasa

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #4 on: June 30, 2023, 06:54:03 AM »
Hello Everyone!

So I boght an 2023 F850GS ADV. I rolled out off BMW and after 100 km I got a 0x3A1B81 fault code it's a Knock sensore problem.
I go back the shop and they search the bike for problem. The cables are fine, the sensore had replaced. I was happy... for 100 km. The problem came back. They sad I have to wait for the new fnf software and I should live with it. I'm now a little fustrated. It's a new bike.. Anyone have a toughts what shod be the problem, or what should I check? I don't want to damage the bike!

Thanks!
Nandi
I think you have encountered a problem with the knock sensor. In addition to the sensor and cables, it might be worth checking the engine control unit (ECU) and related wiring to ensure there are no issues impacting the knock sensor's functionality.
« Last Edit: June 30, 2023, 06:58:16 AM by Mikasa »

Jughead

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #5 on: June 30, 2023, 07:28:05 AM »
I think you have encountered a problem with the knock sensor. In addition to the sensor and cables, it might be worth checking the engine control unit (ECU) and related wiring to ensure there are no issues impacting the knock sensor's functionality.

 ::)  Another AI response!
« Last Edit: June 30, 2023, 12:37:51 PM by Jughead »

Jdorazio1668

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #6 on: July 05, 2023, 12:05:09 AM »
I just signed up to the forum and saw this thread, but no solution to the problem. Figured I would weigh in as I'm a tech at a BMW dealer and have encountered this problem twice. Both times BMW had pinched the wires leading to the knock sensor during assembly at the factory. Ive only seen this issue on the F850 ADV models and in both cases the wires were pinched behind the left side crash bar (the front bolt that's toughest to access). Was this what the dealership said it was when you took the bike back?

alysamueller

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #7 on: July 11, 2023, 05:39:22 AM »
mr mine   
I just signed up to the forum and saw this thread, but no solution to the problem. Figured I would weigh in as I'm a tech at a BMW dealer and have encountered this problem twice. Both times BMW had pinched the wires leading to the knock sensor during assembly at the factory. Ive only seen this issue on the F850 ADV models and in both cases the wires were pinched behind the left side crash bar (the front bolt that's toughest to access). Was this what the dealership said it was when you took the bike back?

What did you do next to solve this problem?

Jdorazio1668

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Re: Fault Code: Knock sensor 1, circuit A, short circuit to ground
« Reply #8 on: July 11, 2023, 08:22:57 PM »
Had to loosen the engine guard then pull the smashed wire or wires out, then repair them. There's enough length on the existing harness to cut the damaged part of the wire off then add a quality electrical connector of your choice then heat shrink over it once it's crimped. I chose to use one of those circular "barrel" shaped connector but other types will work as well.