Pinpoint Test B: DTC P1703 or DTC P1572
Speed Control
Pinpoint Tests
Pinpoint Test B: DTC P1703 Or DTC P1572
Refer to Wiring Diagram Set 31, Speed Control for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information. Diagrams By Number
Normal Operation
When the brake pedal is applied the ABS module receives voltage from the stoplamp switch through circuit 1651 (WH/RD). The ABS module sends a message to the PCM through the High Speed Controller Area Network (HS-CAN) to deactivate the speed control if engaged.
The speed control deactivator switch interrupts the power signal to the PCM through circuit 636 (OG) when the brake pedal is applied firmly. This is a redundant signal to the PCM.
- DTC P1572 (Brake Pedal Switch Circuit) - sets when the PCM does not sense the proper sequence of the brake pedal input signal from both the stoplamp and deactivator switches when the brake pedal is pressed and released.
- DTC P1703 (Brake Switch Out of Self-Test Range) - sets when there is an open or short in the deactivator switch circuits.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Speed control deactivator switch
- PCM
PINPOINT TEST B: DTC P1703 OR DTC P1572
NOTICE: Use the correct probe adaptor(s) when making measurements. Failure to use the correct probe adaptor(s) may damage the connector.
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B1 CHECK THE STOPLAMP SWITCH INPUT TO THE PCM
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the PCM PID BOO while applying and releasing the brake pedal.
- Does the PID agree with the stoplamp switch position?
Yes
GO to B2.
No
REFER to Antilock Brakes / Traction Control Systems to continue diagnosis of the ABS system. Testing and Inspection
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B2 CHECK THE SPEED CONTROL DEACTIVATOR SWITCH FOR CORRECT OPERATION
- Ignition OFF.
- Disconnect: PCM C175b.
- While firmly applying and releasing the brake pedal, measure the voltage between the PCM C175b-9, circuit 636 (OG), harness side and ground.
- Is the voltage greater than 10 volts with the brake pedal released and 0 volts with the brake pedal firmly applied?
Yes
GO to B5.
No
GO to B3.
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B3 CHECK CIRCUIT 1119 (RD) FOR AN OPEN
- Disconnect: Speed Control Deactivator Switch C277.
- Measure the voltage between the speed control deactivator switch C277-2, circuit 1119 (RD), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B4.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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B4 CHECK CIRCUIT 636 (OG) FOR AN OPEN
- Ignition OFF.
- Measure the resistance between the PCM C175b-9, circuit 636 (OG), harness side and speed control deactivator switch C277-1, circuit 636 (OG), 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. REPEAT the self-test.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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B5 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. REPEAT the self-test.
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