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2008 - MX-5 - Engine

DTC P0571 [LF]



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


Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED
  • 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 REPAIR INFORMATION AVAILABILITY
  • 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

INSPECT BRAKE SWITCH CONNECTOR FOR POOR CONNECTION
  • 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 BRAKE SWITCH
  • 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 GROUND CIRCUIT OF BRAKE SWITCH NO.2 FOR OPEN CIRCUIT
  • 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 SIGNAL CIRCUIT OF BRAKE SWITCH NO.1 AND NO.2 FOR SHORT TO GROUND
  • 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

INSPECT PCM CONNECTOR FOR POOR CONNECTION
  • 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 SIGNAL CIRCUIT OF BRAKE SWITCH NO.1 AND NO.2 FOR OPEN CIRCUIT
  • 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

INSPECT SIGNAL CIRCUIT OF BRAKE SWITCH NO.2 FOR SHORT TO POWER SUPPLY
  • 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

INSPECT POWER CIRCUIT OF BRAKE SWITCH NO.1 FOR OPEN CIRCUIT
  • 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 POWER CIRCUIT OF BRAKE SWITCH NO.1 FOR SHORT CIRCUIT TO GROUND
  • 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

VERIFY TROUBLESHOOTING OF DTC P0571 COMPLETED
  • 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

VERIFY AFTER REPAIR PROCEDURE

Yes

Go to the applicable DTC inspection.

(See DTC TABLE [LF].)

No

Troubleshooting completed.




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