Electric Brake Booster System Symptom Troubleshooting - Brake system indicator (red) and brake system indicator (amber) do not go off (Without ACC)

WARNING: This page is about a different car, the 2022 Honda Accord, 2021 Honda Accord, 2020 Honda Accord, 2019 Honda Accord, and 2018 Honda Accord. However, it is still accessible from the selected car via links, so may be relevant.

Brake system indicator (red) and brake system indicator (amber) do not go off

DTC check (Electric brake booster)

-1. Turn the vehicle to the ON mode.

-2. Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame

Is DTC indicated?

YES

Go to indicated DTC's troubleshooting.

Go to step 2.

Gauge control module operation check
-1. Do the gauge control module self-diagnostic function .

Is the gauge control module OK?

YES

Go to step 3.

NO

Replace the gauge control module .
Fuse check 1
-1. Turn the vehicle to the OFF (LOCK) mode with driver's door open.

-2. Wait for 3 minutes.

NOTE: Do not close the driver's door.

-3. Check the following fuse.

Fuse No. A2-4

Is the fuse OK?

YES

The fuse is OK. Reinstall the fuse, then go to step 4.

NO

Replace the fuse. If the fuse blows again, repair a short to body ground in the No. A2-4 fuse circuit.
Fuse check 2
-1. Check the following fuse.

Fuse No. B35

Is the fuse OK?

YES

The fuse is OK. Reinstall the fuse, then go to step 5.

NO

Replace the fuse. Turn the vehicle to the ON mode, then to the OFF (LOCK) mode. If the fuse blows again, repair a short to body ground in the No. B35 fuse circuit.

Open wire check (IG1 OPTION4 line)

-1. Disconnect the following connector.

Electric brake booster 26P connector

-2. Turn the vehicle to the ON mode.

-3. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	Electric brake booster 26P connector: disconnected
Test point 1	Electric brake booster 26P connector No. 24
Test point 2	Body ground

Is there battery voltage?

YES

The IG1 OPTION4 wire is OK. Go to step 6.

Repair an open in the wire between the No. B35 fuse and the electric brake booster.

Open wire check (+B BOOSTER MTR line)

-1. Turn the vehicle to the OFF (LOCK) mode.

-2. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Electric brake booster 26P connector: disconnected
Test point 1	Electric brake booster 26P connector No. 2
Test point 2	Body ground

Is there battery voltage?

YES

The +B BOOSTER MTR wire is OK. Go to step 7.

Repair an open in the wire between the No. A2-4 fuse and the electric brake booster.

Open wire check (GND line)

-1. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Electric brake booster 26P connector: disconnected
Test point 1	Electric brake booster 26P connector No. 1
Test point 2	Body ground

Is there continuity?

YES

The GND wire is OK. Go to step 8.

Repair an open in the wire between the electric brake booster and body ground (G303).

Open wire check (F-CAN A_H, F-CAN A_L lines)

-1. Disconnect the following connectors.

Gauge control module connector A (32P)

-2. Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Electric brake booster 26P connector: disconnected
	Gauge control module connector A (32P): disconnected
Test point 1	Electric brake booster 26P connector No. 26
Test point 2	Gauge control module connector A (32P) No. 20

Test point 1	Electric brake booster 26P connector No. 18
Test point 2	Gauge control module connector A (32P) No. 21

Is there continuity?

YES

Check for loose terminals and poor connections in the electric brake booster 26P connector. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting. If they are OK, replace the electric brake booster .

Repair an open in the wire between the gauge control module and the electric brake booster.