Pinpoint Test C: DTC P1703
Speed Control
Pinpoint Tests
Pinpoint Test C: DTC P1703 (Diesel Engine)
Refer to Wiring Diagram Set 31, Speed Control 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 on circuit CCB08 (VT/WH) to deactivate the speed control if engaged.
The speed control deactivator switch interrupts the voltage signal to the PCM through circuit CMC22 (WH/GN) when the brake pedal is applied firmly. This is a redundant signal to the PCM.
- DTC P1703 (Brake Switch Out Of Self Test Range) - sets when there is an open or short in the deactivator switch circuits or an open or short in the stoplamp circuits.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals, or connectors
- Stoplamp switch
- Speed control deactivator switch
- PCM
PINPOINT TEST C: DTC P1703 (DIESEL ENGINE)
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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C1 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 C2.
No
REFER to Brake Lamp. Testing and Inspection
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C2 CHECK THE STOPLAMP SWITCH (BOO) AND BRAKE PRESSURE SWITCH (BPA) PIDs
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM PIDs BOO (brake pedal top travel) and BPA (brake pressure switch) while applying and releasing the brake pedal as follows:
- Do the PID values agree with the brake pedal position?
Yes
GO to C10.
No
For an incorrect BOO PID value, GO to C3.
For an incorrect BPA PID value, GO to C4.
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C3 CHECK THE STOPLAMP VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: PCM C1381b.
- Ignition ON.
- While applying the brake pedal, measure the voltage between the PCM C1381b-18, circuit CCB08 (WH/VT), 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
For cutaway vehicles, GO to C8.
All other vehicles, GO to C10.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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C4 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH FOR CORRECT OPERATION
- Ignition OFF.
- Disconnect: PCM C1381b and C1381e.
- While firmly applying and releasing the brake pedal, measure the resistance between the PCM C1381b-28, circuit CMC22 (WH/GN), harness side and the PCM C1381e-46, circuit 352 (BN/LG), harness side.
- Is the resistance less than 5 ohms with the brake pedal released and greater than 10,000 ohms with the brake pedal firmly applied?
Yes
GO to C10.
No
GO to C5.
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C5 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH CIRCUIT FOR AN OPEN
- Disconnect: Speed Control Deactivator Switch C1432.
- Measure the resistance between the PCM C1381e-46, circuit 352 (BN/LG), harness side and the speed control deactivator switch C1432-2, circuit LE111 (VT/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to C6.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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C6 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between the speed control deactivator switch C1432-1, circuit CMC22 (WH/GN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
No
GO to C7.
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C7 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH SIGNAL CIRCUIT FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the PCM C1381b-28, circuit CMC22 (WH/GN), harness side and the speed control deactivator switch C1432-1, circuit CMC22 (WH/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new speed control deactivator switch. REFER to Speed Control Deactivator Switch Speed Control Deactivator Switch. 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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C8 CHECK THE BOO RESISTOR VOLTAGE SUPPLY CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: BOO Resistor C3139.
- Ignition ON.
- While applying the brake pedal, measure the voltage between the BOO resistor C3139-1, circuit CCB08 (VT/WH), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to C9.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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C9 CHECK THE BOO RESISTOR GROUND CIRCUIT FOR AN OPEN
- While applying the brake pedal, measure the voltage between the BOO resistor C3139-1, circuit CCB08 (VT/WH), harness side and the BOO resistor C3139-2, circuit GD116 (BK/VT), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new BOO resistor. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
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C10 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. 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. CLEAR the DTCs. TEST the system for normal operation.
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