DTC P0571 (Without Auto Idle Stop System)

DTC P0571  : Brake Pedal Position Switch Circuit Malfunction

NOTE: Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the A/T System (2014 2015), or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016) .
• If the brake pedal is pressed lightly and continuously for 5 minutes or more, this DTC will be stored.

DTC (PGM-FI)

1. Brake lights check 1

   -1. Check the brake lights without the brake pedal pressed.

   Do the brake lights stay on?

   YES 

   Go to step 9.

   NO 

   Go to step 2

2. Brake lights check 2

   -1. Check the brake lights with the brake pedal pressed.

   Do the brake lights come on?

   YES 

   Go to step 3.

   NO 

   Go to step 5.

3. Brake pedal position switch signal check

   -1. Turn the vehicle to the ON mode.

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

   Signal	Current conditions
   	Values	Unit
   BRAKE SWITCH

   Does the signal change ON and OFF when the brake pedal is pressed and released?

   YES 

   Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the brake pedal position switch and the PCM. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.

   NO 

   Go to step 4.

4. Open wire check (STOP SW 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) - Refer to: How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the A/T System (2014 2015)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake pedal pressed
   Test circuit	STOP SW
   Test point 1	PCM connector A (51P) No. 25 (PUR)
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The STOP SW wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

   NO 

   Repair an open in the STOP SW wire between the PCM (A25) and the brake pedal position switch.

5. Brake pedal position switch check

   -1. Test the brake pedal position switch.

   Is the brake pedal position switch normal?

   YES 

   Go to step 6.

   NO 

   Replace the brake pedal position switch.

6. Fuse check

   -1. Check the following fuse.

   Fuse	No. B8 (20 A)
   Location	Main under-hood fuse box

   Is the fuse OK?

   YES 

   Go to step 7.

   NO 

   Replace the No. B8 (20 A) fuse. Also check for a short to ground on the No. B8 (20 A) fuse circuit if needed.

7. Open wire check (+B STOP HORN line)

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

   Test condition	Vehicle OFF (LOCK) mode
   Test circuit	+B STOP HORN
   Test point 1	Brake pedal position switch 4P connector No. 2 (RED)

   Test point 2

   Body ground

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

   Is there battery voltage?

   YES 

   The +B STOP HORN wire is OK. Go to step 8.

   NO 

   Repair an open in the +B STOP HORN wire between the No. B8 (20 A) fuse in the main under-hood fuse box and the brake pedal position switch.

8. Open wire check (STOP SW line)

   -1. Jump the SCS line with the HDS.

   - 2. Disconnect the following connector.

   PCM connector A (51P) - Refer to: How to Troubleshoot the Fuel and Emissions Systems, or How to Troubleshoot the Brake Booster Pressure Monitoring System (2016 2017 2018 2019 2020), or How to Troubleshoot the Fuel and Emissions Systems(With Auto Idle Stop System) (2016), or How to Troubleshoot the A/T System (2014 2015)

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

   Test condition	Vehicle OFF (LOCK) mode
   	Brake pedal pressed
   Test circuit	STOP SW
   Test point 1	PCM connector A (51P) No. 25 (PUR)
   Test point 2	Body ground

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

   Is there battery voltage?

   YES 

   The STOP SW wire is OK. Update the PCM if it does not have the latest software, or substitute a known-good PCM - Refer to: PCM Removal and Installation (2014 2015), or PCM Removal and Installation (2016) .

   NO 

   Repair an open in the STOP SW wire between the PCM (A25) and the brake pedal position switch.

9. Brake pedal position switch installation check

   -1. Remove the brake pedal position switch with the connector is connected.

   - 2. Check the brake lights with the rod of the brake pedal position switch pressed.

   Do the brake lights go off?

   YES 

   The brake pedal position switch is OK, install the brake pedal position switch and adjust the pedal height .

   NO 

   Go to step 10.

10. Brake pedal position switch check

    -1. Test the brake pedal position switch.

    Is the brake pedal position switch normal?

    YES 

    The brake pedal position switch is OK, repair a short to power in the STOP SW wire between the PCM (A25) and the brake pedal position switch.

    NO 

    Replace the brake pedal position switch .