Pinpoint Test B: DTC P0572, P0573 OR P1703
Cruise Control
Pinpoint Tests
Pinpoint Test B: DTC P0572, P0573 OR P1703
Refer to Wiring Diagram Set 31, Cruise Control for schematic and connector information. Diagrams By Number
Refer to Wiring Diagrams for schematic and connector information. Diagrams By Number
Normal Operation
When the brake pedal is applied, the stoplamp switch closes and sends voltage to the PCM to deactivate the cruise control, if engaged.
The cruise control deactivator switch (part of the stoplamp switch) interrupts the voltage signal to the PCM when the brake pedal is applied firmly and passes the cruise control deactivator switch point. This is a redundant signal to the PCM.
- DTC P0572 (Brake Switch A Circuit Low) - sets when the PCM senses a short to ground in the stoplamp circuits.
- DTC P0573 (Brake Switch A Circuit High) - sets when there is an open or short to voltage in the stoplamp circuits.
- DTC P1703 (Brake Switch Out Of Self Test Range) - sets in the PCM during the self-test, when the brake switch input signal is high or does not cycle high and low.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals, or connectors
- Stoplamp switch
- Cruise control deactivator switch (integral to the stoplamp switch)
- PCM
PINPOINT TEST B: DTC P0572, P0573 OR P1703
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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B1 CHECK THE STOPLAMP OPERATION
- Apply and release the brake pedal while observing the stoplamps.
- Do the stoplamps and high mounted stoplamp (if equipped) operate correctly?
Yes
GO to B2.
No
REFER to Exterior Lighting Testing and Inspection.
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B2 CHECK THE STOPLAMP SWITCH (BOO1 AND BOO2) PIDs
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM PIDs BOO1 (brake pedal top travel) and BOO2 (brake pedal bottom travel) while applying and releasing the brake pedal as follows:
- Do the PID values agree with the brake pedal position?
Yes
For cutaway vehicles, GO to B7.
For all other vehicles, GO to B9.
No
For an incorrect BOO1 PID value, GO to B3.
For an incorrect BOO2 PID value, GO to B4.
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B3 CHECK THE STOPLAMP SWITCH CIRCUIT FOR VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175b (4.6L and 5.4L) or C1551b (6.8L).
- Ignition ON.
- For vehicles with 4.6L and 5.4L engines, while applying the brake pedal, measure the voltage between the PCM C175b-13, circuit CCB08 (VT/WH), harness side and ground.
- For vehicles with 6.8L engines, while applying the brake pedal, measure the voltage between the PCM C1551b-8, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts with the brake pedal applied and 0 volts with the brake pedal released?
Yes
GO to B4.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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B4 CHECK THE CRUISE CONTROL DEACTIVATOR VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: Stoplamp Switch C278.
- Ignition ON.
- Measure the voltage between the stoplamp switch C278-2, circuit CBB76 (BU/BN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B5.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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B5 CHECK THE CRUISE CONTROL DEACTIVATOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175b (4.6L and 5.4L) or C1551e (6.8L).
- Ignition ON.
- Measure the voltage between the stoplamp switch C278-3, circuit CES09 (VT/OG), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
No
GO to B6.
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B6 CHECK THE CRUISE CONTROL DEACTIVATOR SIGNAL CIRCUIT FOR AN OPEN
- Ignition OFF.
- For vehicles with 4.6L and 5.4L engines, measure the resistance between the PCM C175b-46, circuit CES09 (VT/OG), harness side and the stoplamp switch C278-3, circuit CES09 (VT/OG), harness side.
- For vehicles with 6.8L engines, measure the resistance between the PCM C1551e-65, circuit CES09 (VT/OG), harness side and the stoplamp switch C278-3, circuit CES09 (VT/OG), harness side.
- Is the resistance less than 5 ohms?
Yes
For cutaway vehicles, GO to B7.
For all other vehicles, INSTALL a new stoplamp switch. REFER Exterior Lighting Service and Repair. CLEAR the DTCs. TEST the system for normal operation.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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B7 CHECK THE BOO RESISTOR VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: BOO Resistor C2403.
- Ignition ON.
- While applying the brake pedal, measure the voltage between the BOO resistor C2403-1, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B8.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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B8 CHECK THE BOO RESISTOR GROUND CIRCUIT FOR AN OPEN
- While applying the brake pedal, measure the voltage between the BOO resistor C2403-1, circuit CCB08 (VT/WH), harness side and the BOO resistor C2403-2, circuit GD116 (BK/VT), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new BOO resistor. CLEAR the DTCs. TEST the system for normal operation.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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B9 CHECK FOR CORRECT PCM OPERATION
- Connect: All Disconnected Connectors.
- Disconnect all the PCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the PCM connectors and make sure they are seated correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.
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