DTC P0571

id010205809000

DTC P0571

Brake switch input 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 illuminate.
•  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
•  DSC HU/CM malfunction
•  Open circuit in wiring harness between battery positive terminal and brake switch terminal B
•  Short to GND in wiring harness between battery positive terminal and brake switch terminal B
•  Open circuit in wiring harness between brake switch terminal D and DSC HU/CM terminal AD
•  Short to power supply in wiring harness between brake switch terminal D and DSC HU/CM terminal AD
•  Short to GND in wiring harness between brake switch terminal D and DSC HU/CM terminal AD
•  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 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
VERIFY RELATED PENDING CODE OR STORED DTC
•  Turn the ignition switch off, then to the ON position (Engine off).
•  Verify the related PENDING CODE or stored DTCs.
•  Are other DTCs present?
Yes
Go to the appropriate DTC inspection.
(See DTC TABLE.)
No
Go to the next step.
4
INSPECT BRAKE SWITCH CONNECTOR FOR POOR CONNECTION
•  Turn the ignition switch off.
•  Disconnect the brake switch connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 11.
No
Go to the next step.
5
INSPECT BRAKE SWITCH NO.1 POWER CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GND
•  Turn the ignition switch to the ON position (Engine off).
•  Measure the voltage between brake switch terminal B (wiring harness-side) and body GND.
•  Is the voltage B+?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit or short to GND, then go to Step 11.
6
INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR SHORT TO GND
•  Turn the ignition switch off.
•  Inspect for continuity between brake switch terminal D (wiring harness-side) and body GND.
•  Is there continuity?
Yes
Repair or replace the wiring harness for a possible short to GND, then go to Step 11.
No
Go to the next step.
7
INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Turn the ignition switch to the ON position (Engine off).
•  Measure the voltage between brake switch terminal D (wiring harness-side) and body GND.
•  Is the voltage B+?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 11.
No
Go to the next step.
8
INSPECT BRAKE SWITCH NO.1
•  Inspect the brake switch No.1.
•  Is there any malfunction?
Yes
Replace the brake switch, then go to Step 11.
(See BRAKE PEDAL REMOVAL/INSTALLATION.)
No
Go to the next step.
9
INSPECT DSC HU/CM CONNECTOR FOR POOR CONNECTION
•  Turn the ignition switch off.
•  Disconnect the DSC HU/CM connector.
•  Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the terminal, then go to Step 11.
No
Go to the next step.
10
INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR OPEN CIRCUIT
•  Turn the ignition switch off.
•  Inspect for continuity between brake switch terminal D (wiring harness-side) and DSC HU/CM terminal AD (wiring harness-side).
•  Is there continuity?
Yes
Go to the next step.
No
Repair or replace the wiring harness for a possible open circuit, then go to the next step.
11
VERIFY TROUBLESHOOTING OF DTC P0571 COMPLETED
•  Make sure to reconnect all disconnected connectors.
•  Clear the DTC from the PCM memory using the WDS or equivalent.
•  Start the engine.
•  Operate the brake pedal.
•  Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION.)
No
Go to the next step.
12
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
DTC troubleshooting completed.