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HOMESERVICE MANUALSACURA2015RLXREPAIR AND DIAGNOSISACCESSORIES & EQUIPMENTCRUISE CONTROL SYSTEMSADAPTIVE CRUISE CONTROL SYSTEM - DIAGNOSTICS (EXCEPT HYBRID)DTC TROUBLESHOOTINGDTC C0041-14 (ADAPTIVE CRUISE CONTROL UNIT) (2014 2015 2016 2017)

2015 Acura RLX

DTC C0041-14 (Adaptive Cruise Control Unit) (2014 2015 2016 2017)

2015 Acura RLXSECTION DTC C0041-14 (Adaptive Cruise Control Unit) (2014 2015 2016 2017)

DTC C0041-14 : Brake Switch Signal Error

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the how to troubleshooting information .

DTC Description	DTC	Freeze Frame
C0041-14 Brake Switch Signal Error

DTC (ACC)

If DTC C0041-14 is stored at the same time as DTC U0029-00 troubleshoot DTC U0029-00 first, then recheck for DTC C0041-14.

DTC Description	DTC	Freeze Frame
U0029-00 Communication Line Error

DTC check

-1. Turn the vehicle to the ON mode.

-2. Clear the DTC with the HDS.

-3. Turn the vehicle to the OFF (LOCK) mode, then the ON mode.

-4. Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame
C0041-14 Brake Switch Signal Error

Is DTC C0041-14 indicated?

YES

Go to step 2.

Intermittent failure, the system is OK at this time.

Brake pedal position switch check 1

-1. Turn the vehicle to the ON mode.

-2. Check the parameter (s) below with the HDS.

Signal	Current conditions
Signal	Values	Unit
BRAKE SW (N.O.)

Does BKSW (N.O.) indicate OFF?

YES

Go to step 3.

If BKSW (N.C.) indicate OFF, go to step 10.

If BKSW (N.C.) indicate ON, do the brake pedal adjustment .

Brake pedal position switch check 2

-1. Check the parameter (s) below with the HDS.

Signal	Current conditions
Signal	Values	Unit
BRAKE SW (N.C.)

Does BKSW (N.C.) indicate OFF?

YES

Go to step 4.

Go to step 6.

Brake pedal position switch check 3

-1. Check the BRAKE SWITCH parameter (s) below with the HDS under this condition.

FRONT BRAKE PRESSURE with pressing the brake pedal in 2 MPa.

Signal	Current conditions
Signal	Values	Unit
BRAKE P
BRAKE SW (N.O.)

Does BKSW (N.O.) indicate ON?

YES

Go to step 5.

If BKSW (N.C.) indicate OFF, do the brake pedal adjustment .

If BKSW (N.C.) indicate ON, go to step 12.

Brake pedal position switch check 4

-1. Check the BRAKE SWITCH parameter (s) below with the HDS under this condition.

FRONT BRAKE PRESSURE with pressing the brake pedal in 2 MPa.

Signal	Current conditions
Signal	Values	Unit
BRAKE P
BRAKE SW (N.C.)

Does BKSW (N.C.) indicate ON?

YES

The system is OK at this time.

Go to step 17.

Fuse check 1

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

-2. Check the following fuse.

Fuse	No. C1 (15 A)
Location	Under-hood fuse/relay box

Is the fuse OK?

YES

The fuse is OK. Reinstall the fuse, then go to step 7.

Replace the fuse. If the fuse blows again, repair the short to ground on the No. C1 (15 A) fuse circuit.

Brake pedal position switch check 5
-1. Check the brake pedal position switch .

Is the brake pedal position switch OK?

YES

Go to step 8.

NO

Replace the brake pedal position switch .

Open wire check (IG1 ACG line)

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

-2. Disconnect the following connector.

Brake pedal position switch 4P connector

-3. Turn the vehicle to the ON mode.

-4. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	Brake pedal position switch 4P connector: disconnected
Test circuit	IG1 ACG
Test point 1	Brake pedal position switch 4P connector No. 4 (LT BLU)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

The IG1 ACG wire is OK. Go to step 9.

Repair an open in the wire between the No. C1 (15 A) fuse in the under-hood fuse /relay box and the brake pedal position switch.

Open wire check (BKSWNC line)

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

-2. Reconnect the following connector.

Brake pedal position switch 4P connector

-3. Jump the SCS line with the HDS.

-4. Disconnect the following connector.

PCM connector A (51P)

-5. Turn the vehicle to the ON mode.

-6. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	PCM connector A (51P): disconnected
Test circuit	BKSWNC
Test point 1	PCM connector A (51P) No. 24 (YEL)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

The BKSWNC wire is OK. Go to step 19.

Repair an open in the wire between the PCM and the brake pedal position switch.

Brake pedal position switch check 2
-1. Check the brake pedal position switch .

Is the brake pedal position switch OK?

YES

Go to step 11.

NO

Replace the brake pedal position switch .

Shorted wire check (STOP SW line to power)

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

-2. Reconnect the following connector.

Brake pedal position switch 4P connector (if disconnected)

-3. Jump the SCS line with the HDS.

-4. Disconnect the following connector.

PCM connector A (51P)

-5. Turn the vehicle to the ON mode.

-6. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	PCM connector A (51P): disconnected
Test circuit	STOP SW
Test point 1	PCM connector A (51P) No. 25 (LT GRN)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

Repair a short to power in the wire between the brake pedal position switch and the brake lights relay or the PCM.

The STOP SW wire is OK. Go to step 19.

Brake lights check
-1. Check the brake lights when pressing the brake pedal.

Are the brake lights OK?

YES

Go to step 13.

NO

Go to step 14.

Open wire check (BKSWNC line)

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

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.

PCM connector A (51P)

-4. Turn the vehicle to the ON mode.

-5. Measure the voltage between test points 1 and 2.

Test condition	Vehicle ON mode
	PCM connector A (51P): disconnected
Test circuit	BKSWNC
Test point 1	PCM connector A (51P) No. 24 (YEL)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

The BKSWNC wire is OK. Go to step 19.

Repair an open in the wire between the PCM and the brake pedal position switch.

Fuse check

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

-2. Check the following fuse.

Fuse	No. C19 (7.5 A)
Location	Under-hood fuse/relay box

Is the fuse OK?

YES

The fuse is OK. Reinstall the fuse, then go to step 15.

Replace the fuse. If the fuse blows again, repair the short to ground on the No. C19 (7.5 A) fuse circuit.

Brake pedal position switch check 4
-1. Check the brake pedal position switch .

Is the brake pedal position switch OK?

YES

Go to step 16.

NO

Replace the brake pedal position switch .

Open wire check (+B STOP line)

-1. Disconnect the following connector.

Brake pedal position switch 4P connector (if connected)

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

Test condition	Vehicle OFF (LOCK) mode
	Brake pedal position switch 4P connector: disconnected
Test circuit	+B STOP
Test point 1	Brake pedal position switch 4P connector No. 2 (PUR)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

Repair an open in the wire between the brake pedal position switch and the brake lights relay or the PCM.

Repair an open in the wire between the No. C19 (7.5 A) fuse in the under-hood fuse /relay box and the brake pedal position switch.

Brake pedal position switch check 5
-1. Check the brake pedal position switch .

Is the brake pedal position switch OK?

YES

Go to step 18.

NO

Replace the brake pedal position switch .

Shorted wire check (STOP SW line to power)

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

-2. Jump the SCS line with the HDS.

-3. Disconnect the following connector.

PCM connector A (51P)

-4. Measure the voltage between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	PCM connector A (51P): disconnected
Test circuit	STOP SW
Test point 1	PCM connector A (51P) No. 25 (LT GRN)
Test point 2	Body ground

Courtesy of HONDA, U.S.A., INC.

Is there battery voltage?

YES

Repair a short to power in the wire between the brake pedal position switch and the brake light relay or the PCM.

The STOP SW wire is OK. Go to step 19.

PCM check (update)

-1. Reconnect the following connector.

PCM connector A (51P)

-2. Update the PCM if it does not have the latest software .

-3. Turn the vehicle to the OFF (LOCK) mode.

-4. Turn the vehicle to the ON mode, and wait 20 seconds.

-5. Check for DTCs with the HDS.

DTC Description	Confirmed DTC	Pending DTC	Freeze Frame

Is DTC C0041-14 indicated?

YES

Check for loose terminals in the PCM connector A (51P). If the PCM was updated and the symptom/indication is still present, replace the PCM .

Troubleshooting is complete. If any other DTCs are indicated, go to the indicated DTC's troubleshooting.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.