Test AY: Brake Pressure Switch
PINPOINT TEST AY: BRAKE PRESSURE SWITCHFlow Chart:
This pinpoint test is intended to diagnose the following:
- brake pressure switch
- brake pressure switch harness circuits BPS and B+
- powertrain control module (PCM) (12A650)
Brake Pressure Switch Connector
Brake Pressure Switch Connector:
PCM Connector
PCM Connector:
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AY1 : CHECK THE BRAKE PRESSURE SWITCH SIGNAL
NOTE: Full brake pedal application may be necessary to correctly operate the brake pressure switch.
- Ignition ON, engine OFF.
- Access the PCM and monitor the BPA PID.
- Monitor the BPA PID while applying and releasing the brake pedal.
- Does the BPA PID state change when the brake pedal is fully applied and released?
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AY2 : CHECK THE BRAKE PRESSURE SWITCH SIGNAL VOLTAGE
NOTE: Full brake pedal application may be necessary to correctly operate the brake pressure switch.
- Ignition OFF.
- PCM connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
- Fully apply and release the brake pedal while measuring the voltage.
- Is voltage greater than 10 volts with the brake pedal released and less than 1 volt with the brake pedal fully applied?
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AY3 : CHECK THE BRAKE PRESSURE SWITCH VOLTAGE
- Ignition OFF.
- Brake Pressure Switch connector disconnected.
- Ignition ON, engine OFF.
- Measure the voltage between:
- Is the voltage greater than 10 V?
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AY4 : CHECK THE BRAKE PRESSURE SWITCH
NOTE: Full brake pedal application may be necessary to correctly operate the brake pressure switch.
- Ignition OFF.
- Measure the resistance between:
- Fully apply and release the brake pedal while measuring the resistance.
- Is the resistance less than 5 ohms with the pedal released and greater than 10,000 ohms with the pedal fully applied?
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AY5 : CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test and verify the concern is still present.
- Is the concern still present?
