DTC P0571 [L8, LF]

id0102b1809000

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 illuminate.
•  FREEZE FRAME DATA (Mode 2/Mode 12) is available.
•  The DTC is stored in the PCM memory.
POSSIBLE CAUSE
Note
•  Inspect the brake switch with it installed to the brake pedal, otherwise the brake switch may not operate normally. If the brake switch is removed from the brake pedal, replace the brake switch with a new one.
•  Brake switch connector or terminals malfunction
•  Open circuit in wiring harness between brake switch terminal C and body ground
•  Open circuit or short to ground in wiring harness between battery positive terminal and brake switch terminal B
―  Short to ground in wiring harness between battery positive terminal and brake switch terminal B
―  STOP 10 A fuse malfunction
―  Open circuit in wiring harness between battery positive terminal and brake switch terminal B
•  Short to ground in wiring harness between the following terminals:
―  Brake switch terminal D and PCM terminal 1AB
―  Brake switch terminal A and PCM terminal 1AF
•  PCM connector or terminals malfunction
•  Short to power supply in wiring harness between brake switch terminal D and PCM terminal 1AB
•  Open circuit in wiring harness between the following terminals:
―  Brake switch terminal D and PCM terminal 1AB
―  Brake switch terminal A and PCM terminal 1AF
•  Brake switch malfunction
•  PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION
1
VERIFY FREEZE FRAME DATA (MODE 12) AND DIAGNOSTIC MONITORING TEST RESULTS HAVE BEEN RECORDED
•  Have the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS (other related) been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA (Mode 12) and DIAGNOSTIC MONITORING TEST RESULTS on repair order, then go to the next step.
2
VERIFY RELATED SERVICE INFORMATION AVAILABILITY
•  Verify related Service Information availability.
•  Is any related Service Information available?
Yes
Perform repair or diagnosis according to the available Service Information.
•  If the vehicle is not repaired, go to the next step.
No
Go to the next step.
3
INSPECT BRAKE SWITCH CONNECTOR AND TERMINALS
•  Turn the ignition switch off.
•  Disconnect brake switch connector.
•  Inspect for poor connection (such as damaged, pull-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 10.
No
Go to the next step.
4
INSPECT BRAKE SWITCH NO.2 GROUND CIRCUIT FOR OPEN CIRCUIT
•  Brake switch connector is disconnected.
•  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 a possible open circuit, then go to Step 10.
5
INSPECT BRAKE SWITCH NO.1 POWER SUPPLY CIRCUIT FOR OPEN CIRCUIT OR SHORT TO GROUND
•  Brake switch connector is disconnected.
•  Turn the ignition switch to the ON position.
•  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
Inspect the STOP 10 A fuse.
•  If the fuse is melt:
―  Repair or replace the wiring harness for a possible short to ground.
―  Replace the fuse.
•  If the fuse is deterioration:
―  Replace the fuse.
•  If the fuse is normal:
―  Repair or replace the wiring harness for a possible open circuit.
Go to Step 10.
6
INSPECT BRAKE SWITCH NO.1 AND NO.2 SIGNAL CIRCUIT FOR SHORT TO GROUND
•  Brake switch connector is disconnected.
•  Turn the ignition switch off.
•  Inspect for continuity between the following terminal (wiring harness-side) and body ground:
―  Brake switch terminal D
―  Brake switch terminal A
•  Is there continuity?
Yes
If the short to ground circuit could be detected:
•  Repair or replace the wiring harness for a possible short to ground.
If the short to ground circuit could not be detected:
•  Replace the PCM (short to ground in PCM internal circuit).
Go to Step 10.
No
Go to the next step.
7
INSPECT PCM CONNECTOR AND TERMINALS
•  Disconnect PCM connector.
•  Inspect for poor connection (such as damaged, pull-out pins, corrosion).
•  Is there any malfunction?
Yes
Repair or replace the connector or terminals, then go to Step 10.
No
Go to the next step.
8
INSPECT BRAKE SWITCH NO.1 SIGNAL CIRCUIT FOR SHORT TO POWER SUPPLY
•  Brake switch and PCM connectors are disconnected.
•  Turn the ignition switch to the ON position (engine off).
•  Measure the voltage between PCM terminal 1AB (wiring harness-side) and body ground.
•  Is there any voltage?
Yes
Repair or replace the wiring harness for a possible short to power supply, then go to Step 10.
No
Go to the next step.
9
INSPECT BRAKE SWITCH NO.1 AND NO.2 SIGNAL CIRCUIT FOR OPEN CIRCUIT
•  Brake switch and PCM connectors are disconnected.
•  Turn the ignition switch off.
•  Inspect for continuity between the following terminals (wiring harness-side):
―  Brake switch terminal D and PCM terminal 1AB
―  Brake switch terminal A and PCM terminal 1AF
•  Is there continuity?
Yes
Replace the brake switch, then go to the next step.
(See BRAKE PEDAL REMOVAL/INSTALLATION.)
No
Repair or replace the wiring harness for a possible open circuit, then go to the next step.
10
VERIFY DTC TROUBLESHOOTING 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.
•  Perform the DTC Reading Procedure.
•  Is the same DTC present?
Yes
Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION [L8, LF].)
No
Go to the next step.
11
VERIFY AFTER REPAIR PROCEDURE
•  Perform the “AFTER REPAIR PROCEDURE”.
•  Are any DTCs present?
Yes
Go to the applicable DTC troubleshooting.
(See DTC TABLE [L8, LF].)
No
DTC troubleshooting completed.