FD: Brake Pedal Position (BPP) Switch

FD: Introduction See: FD: Brake Pedal Position (BPP) Switch - Introduction

FD1 KOER DTC P0703 OR P1703: VERIFY BRAKE PEDAL WAS APPLIED

Was the brake pedal applied and released during KOER Self-Test?
Yes

• For Continental and Town Car:
• REFER to Lighting and Horns for further diagnosis of the lighting control module (LCM) system.
• For Windstar:
• REFER to Lighting and Horns for further diagnosis of the Rear Electronic Module (REM).
• All Others:
• KEY ON. GO to FD3

.

No

• RERUN KOER Self-Test. APPLY and RELEASE brake pedal.

FD2 KOEO DTC P0703 OR P1703: VERIFY BRAKE PEDAL WAS NOT APPLIED

Was the brake pedal applied during KOEO Self-Test?
Yes

• RERUN KOEO Self-Test. Avoid applying brake pedal during test.

No

• For Continental and Town Car:
• REFER to Lighting and Horns for further diagnosis of the lighting control module (LCM) system.
• For Windstar:
• REFER to Lighting and Horns for further diagnosis of the Rear Electronic Module (REM).
• All others:
• KEY ON. GO to FD3

.

FD3 DTCS P0703, P1572 AND P1703: CHECK OPERATION OF STOPLAMPS

• Apply and release the brake pedal several times and observe stoplamp operation.

Do the stoplamps operate normally?
Yes

• GO to FD4

.

No

• For LS6/LS8:
• REFER to Lighting and Horns for further diagnosis of the rear electrical module (REM).
• For all others:
• GO to FD5

for stoplamps never on.

• GO to FD7

for stoplamps always on.

FD4 CHECK FOR PCM BPP PID CYCLING

• Key on, engine off.
• Access BPP PID.

Note: If BPP PID is not accessible, GO to FD10.

• Apply and release the brake pedal several times while viewing the BPP PID.

Does the BPP PID cycle ON/OFF?
Yes

• KEY OFF. Unable to duplicate or identify fault at this time. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

.

No

• KEY OFF. GO to FD10

.

FD5 CHECK B+ VOLTAGE TO BRAKE PEDAL POSITION SWITCH

Note: Check the condition of the stoplamp bulbs before starting this test.

• Disconnect BPP switch.
• Measure B+ input voltage between BPP switch harness connector and chassis ground.

Is voltage greater than 10 volts?
Yes

• GO to FD6

.

No

• VERIFY integrity of fuse for B+ to brake pedal position switch.

If OK, REPAIR open in B+ circuit. If fuse is damaged, check B+ circuit, BPP
circuit, stop lamp PWR circuit and any other associated circuits (REFER to
Wiring Diagrams) for short to ground. REPAIR as necessary.

FD6 VERIFY INTEGRITY OF BRAKE PEDAL POSITION SWITCH

• Connect digital multimeter test probes to BPP switch terminals at the BPP switch.
• Apply brake pedal while monitoring reading.

Is the resistance less than 5.0 ohms?
Yes

• REPAIR open circuit between BPP switch and stoplamp ground.

No

• REPLACE BPP switch.

FD7 VERIFY BRAKE PEDAL POSITION SWITCH IS NOT ALWAYS CLOSED

• Disconnect BPP switch.
• Key on, engine off.

Are stoplamps still on?
Yes

• KEY OFF. GO to FD8

.

No

• VERIFY proper installation of BPP switch. If OK, REPLACE switch.

FD8 CHECK FOR SHORT TO POWER IN PCM

• Disconnect PCM.
• Key on.

Are stoplamps still on?
Yes

• KEY OFF. GO to FD9

.

No

• KEY OFF. REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM

).

FD9 CHECK STOPLAMP CIRCUIT FOR SHORT TO POWER IN HARNESS

• One at a time, disconnect all modules associated with the stoplamp circuit (Refer to Wiring Diagrams). After disconnecting each module, turn key on and observe stoplamps. Turn key off. Repeat until each associated module has been disconnected or stoplamps turn off.

Did stoplamps turn off when any of the modules were disconnected?
Yes

• REFER to the diagnostic/repair information for further diagnosis of appropriate

module.

No

• REPAIR short to power in stoplamp circuit.

FD10 CHECK FOR BPP CIRCUIT CYCLING

Note: Refer to the PCM connector pin numbers in the beginning of this Pinpoint Test.

• KEY OFF.
• Disconnect PCM.
• Measure voltage between BPP circuit at the PCM harness connector and ground while applying and releasing the brake.

Does the voltage cycle?
Yes

• For LS6/LS8, Explorer/Mountaineer (150 PIN PCM):

GO to FD11
.

• For all others:
• REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

No

• REPAIR open in BPP circuit to PCM.

FD11 CHECK FOR BPA CIRCUIT CYCLING

Note: Refer to the PCM connector pin numbers in the beginning of this Pinpoint Test.

• Disconnect PCM.
• Measure voltage between BPA circuit at the PCM harness connector and ground while applying and releasing the brake.

Does the voltage cycle?
Yes

• REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

No

• GO to FD12

.

FD12 CHECK BPA CIRCUIT FOR OPEN IN HARNESS

• Disconnect BPA deactivator switch.
• Measure resistance of BPA circuit between PCM harness connector pin and BPA deactivator switch harness connector.

Is the resistance less than 5 ohms?
Yes

• GO to FD13

.

No

• REPAIR open in BPA circuit to PCM.

FD13 CHECK BPA DEACTIVATOR SWITCH

• Connect digital multimeter test probes to BPA switch terminals at the BPA switch.
• Apply brake pedal while monitoring reading.

Is the resistance less than 5 ohms with the brake pedal released and greater than 10,000 ohms with the brake pedal depressed?
Yes

• REPAIR VPWR circuit to BPA switch.

No

• REPLACE BPA deactivator switch.