DTC P0571

Brake switch circuit problem

DETECTION CONDITION

• The PCM monitors switching in conjunction with brake switches No.1 and No.2. If either No.1 or No.2 do not switch for a continuous five times even though either No.1 or No.2 is switched from off to on or from on to off, P0571 is detected.

Diagnostic support note

• This is a continuous monitor (Other).

• The MIL does not comes on.

• PENDING CODE is available if the PCM detects the above malfunction condition.

• FREEZE FRAME DATA is available.

• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Brake switch malfunction

• Connector or terminal malfunction

• Open circuit in wiring harness between brake switch terminal A and PCM terminal 1AF

• Open circuit in wiring harness between brake switch terminal C and body ground

• Open circuit in wiring harness between battery positive terminal and brake switch terminal B

• Open circuit in wiring harness between brake switch terminal D and PCM terminal 1AB

• Short to ground in wiring harness between brake switch terminal D and PCM terminal 1AB

• Short to power supply in wiring harness between brake switch terminal D and PCM terminal 1AB

• Short to ground in wiring harness between brake switch terminal A and PCM terminal 1AF

• PCM malfunction

STEP

INSPECTION

ACTION

1

• Has FREEZE FRAME DATA been recorded?

Yes

Go to the next step.

No

Record the FREEZE FRAME DATA on the repair order, then go to the next step.

2

• Verify related Service Bulletins and/or on-line repair information availability.

• Is any related repair information available?

Yes

Perform repair or diagnosis according to the available repair information.

• If the vehicle is not repaired, go to the next step.

No

Go to the next step.

3

• Turn the ignition switch off.

• Disconnect the brake switch connector.

• Inspect for poor connection (such as damaged, pull-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 12.

No

Go to the next step.

4

• Inspect the brake switch.

• Is the brake switch normal?

Yes

Go to the next step.

No

Replace brake switch, then go to Step 12.

(See BRAKE PEDAL REMOVAL/INSTALLATION.)

5

• Inspect for continuity between brake switch terminal C (wiring harness-side) and body ground.

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit, then go to Step 12.

6

• Inspect for continuity between the following terminal:

• Brake switch terminal A (wiring harness-side) and body ground.

• Brake switch terminal D (wiring harness-side) and body ground.

• Is there continuity?

Yes

Repair or replace the wiring harness for short to ground circuit, then go to Step 12.

No

Go to the next step.

7

• Turn the ignition switch off.

• Disconnect PCM connector.

• Inspect for poor connection (such as damaged, pull-out pins, corrosion).

• Is there any malfunction?

Yes

Repair or replace the terminal, then go to Step 12.

No

Go to the next step.

8

• Inspect for continuity between the following terminal:

• Brake switch terminal A (wiring harness-side) and PCM terminal 1AF (wiring harness-side)

• Brake switch terminal D (wiring harness-side) and PCM terminal 1AB (wiring harness-side)

• Is there continuity?

Yes

Go to the next step.

No

Repair or replace the wiring harness for open circuit, then go to Step 12.

9

• Turn the ignition switch to the ON position (Engine off).

• Measure the voltage between brake switch terminal A (wiring harness-side) and body ground.

• Is the voltage B+?

Yes

Repair or replace the wiring harness for short to power circuit, then go to Step 12.

No

Go to the next step.

10

• Measure the voltage between brake switch terminal B (wiring harness-side) and body ground.

• Is the voltage B+?

Yes

Go to the next step.

No

Repair or replace the wiring harness for a possible open circuit, then go to step 12.

11

• Inspect for continuity between the following terminal:

• Brake switch terminal B (wiring harness-side) and body ground.

• Is there continuity?

Yes

Repair or replace the wiring harness for a possible short to ground, then go to the next step.

No

Go to the next step.

12

• Make sure to reconnect all disconnected connectors.

• Clear the DTC from the PCM memory using the M-MDS.

• Turn the ignition switch to the ON position (Engine off).

• Depress and release the brake pedal more than 5 times.

• Is the same DTC present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION [LF].)

No

Go to the next step.

13

• Perform “AFTER REPAIR PROCEDURE”.

  (See AFTER REPAIR PROCEDURE [LF].)

• Is any DTC present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [LF].)

No

Troubleshooting completed.