Pinpoint Test C: DTC P0579 Or DTC P0581
Speed Control
Pinpoint Tests
Pinpoint Test C: DTC P0579 Or DTC P0581
Refer to Wiring Diagram Set 31, Speed Control for schematic and connector information. Diagrams By Number
Normal Operation
The PCM sends a signal through circuit VES10 (WH) to the speed control switches which passes through the clockspring. The return signal is sent through circuit RES08 (GN/BN) and the clockspring.
- DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - may set when the speed control switch circuits are open, shorted to voltage or ground.
- DTC P0581 (Cruise Control Multifunction Input A Circuit High) - sets when the speed control switch circuits are open or shorted to voltage.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Clockspring
- Speed control switch
- PCM
PINPOINT TEST C: DTC P0579 OR DTC P0581
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 SPEED CONTROL SWITCH
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Press each speed control switch button while monitoring the SCCS PID (speed control switch).
- Does the PID value agree with the switch position?
Yes
The system is operating correctly at this time. CLEAR the DTCs. TEST the system for normal operation.
No
If only one switch does not display the correct PID value, INSTALL a new speed control switch. REFER to Speed Control Switch Speed Control Switch. CLEAR the DTCs. TEST the system for normal operation.
Otherwise, GO to C2.
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C2 CHECK THE SPEED CONTROL SWITCH CIRCUITRY FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: PCM C175b.
- Ignition ON.
- Turn the parking lamps on.
- Measure the voltage between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Is any voltage present?
Yes
TURN the parking lamps off. GO to C3 .
No
TURN the parking lamps off. GO to C5 .
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C3 CHECK CIRCUITS RES08 (GN/BN) AND VES10 (WH) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Clockspring C218a.
- Ignition ON.
- Turn the parking lamps on.
- Measure the voltage between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
No
TURN the parking lamps off. GO to C4 .
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C4 CHECK THE CLOCKSPRING FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Connect: Clockspring C218a.
- Remove the driver air bag module.
- Connect the restraint system diagnostic tool (418-F395) to the upper clockspring air bag connector.
- Disconnect: Upper Clockspring Connector.
- WARNING: Make sure no one is in the vehicle and there is nothing blocking or placed in front of any air bag module when the battery is connected. Failure to follow these instructions may result in serious personal injury in the event of an accidental deployment.
- Connect the battery.
- Ignition ON.
- Turn the parking lamps on.
- Measure the voltage between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Is any voltage present?
Yes
INSTALL a new clockspring. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
No
INSTALL a new speed control switch. REFER to Speed Control Switch Speed Control Switch. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
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C5 CHECK THE SPEED CONTROL SWITCH CIRCUITRY FOR A SHORT TO GROUND
- Ignition OFF.
- Measure the resistance between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to C8.
No
GO to C6.
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C6 CHECK THE CLOCKSPRING FOR A SHORT TO GROUND
- Remove the driver air bag module.
- Disconnect: Upper Clockspring.
- Measure the resistance between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new speed control switch. REFER to Speed Control Switch Speed Control Switch. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
No
GO to C7.
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C7 CHECK CIRCUITS RES08 (GN/BN) AND VES10 (WH) FOR A SHORT TO GROUND
- Disconnect: Clockspring C218a.
- Measure the resistance between the PCM C175b-57, circuit RES08 (GN/BN), harness side and ground; and between the PCM C175b-56, circuit VES10 (WH), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
INSTALL a new clockspring. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit in question. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
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C8 CHECK THE SPEED CONTROL SWITCH CIRCUITRY FOR AN OPEN
- Disconnect: Clockspring C218a.
- Measure the resistance between the PCM C175b-57, circuit RES08 (GN/BN), harness side and the clockspring C218a-14, circuit RES08 (GN/BN), harness side.
- Measure the resistance between the PCM C175b-56, circuit VES10 (WH), harness side and the clockspring C218a-15, circuit VES10 (WH), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to C9.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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C9 CHECK THE CLOCKSPRING
- Remove the driver air bag module.
- Disconnect: Upper Clockspring.
- Measure the resistance between the clockspring C218a-14, component side and the upper clockspring pin 9, component side.
- Measure the resistance between the clockspring C218a-15, component side and the upper clockspring pin 8, component side.
- Are the resistances less than 5 ohms?
Yes
GO to C10.
No
INSTALL a new clockspring. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
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C10 CHECK THE SPEED CONTROL SWITCH
- Measure the resistance between the upper clockspring pin 8, harness side and the upper clockspring pin 9, harness side.
- Is the resistance between 4,095 and 4,526 ohms?
Yes
GO to C11.
No
INSTALL new speed control switch. REFER to Speed Control Switch Speed Control Switch. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
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C11 CHECK FOR CORRECT PCM OPERATION
- 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. INSTALL the driver air bag module. 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. INSTALL the driver air bag. CLEAR the DTCs. REPEAT the self-test.
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