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 248 (TN/OG) to the speed control switches. The return signal is grounded through circuit 133 (BK). Both circuits pass through the clockspring.
- DTC P0579 (Cruise Control Multifunction Input A Circuit Range/Performance) - sets when the speed control switch circuits are open, shorted to voltage or shorted to ground.
- DTC P0581 (Cruise Control Multifunction Input A Circuit High) - sets when the speed control switch circuits are shorted to voltage or open.
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-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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 248 (TN/OG) AND 133 (BK) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: Clockspring C2274.
- Ignition ON.
- Turn the parking lamps on.
- Measure the voltage between the PCM C175b-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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 C2274.
- Remove the driver air bag module.
- Connect the restraint system diagnostic tools (418-F395) to the upper clockspring air bag connector.
- Disconnect: Upper Clockspring.
- 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-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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. DISCONNECT the battery. INSTALL the driver air bag module. CLEAR the DTCs. REPEAT the self-test.
No
GO to C7.
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C7 CHECK CIRCUITS 248 (TN/OG) AND 133 (BK) FOR A SHORT TO GROUND
- Disconnect: Clockspring C2274.
- Measure the resistance between the PCM C175b-19, circuit 248 (TN/OG), harness side and ground; and between the PCM C175b-30, circuit 133 (BK), 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
- Measure the resistance between the PCM C175b-19, circuit 248 (TN/OG), harness side and the PCM C175b-30, circuit 133 (BK), harness side.
- Is the resistance between 4,100 and 4,500 ohms?
Yes
GO to C11.
No
GO to C9.
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C9 CHECK CIRCUITS 248 (TN/OG) AND 133 (BK) FOR AN OPEN
- Disconnect: Clockspring C2274.
- Measure the resistance between the PCM C175b-19, circuit 248 (TN/OG), harness side and the clockspring C2274-4, circuit 248 (TN/OG), harness side.
- Measure the resistance between the PCM C175b-30, circuit 133 (BK), harness side and the clockspring C2274-5, circuit 133 (BK), harness side.
- Are the resistances less than 5 ohms?
Yes
GO to C10.
No
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
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C10 CHECK THE CLOCKSPRING
- Remove the driver air bag module.
- Disconnect: Upper Clockspring.
- Measure the resistance between the clockspring C2274 pin 4, component side and the upper clockspring connector pin 2, component side.
- Measure the resistance between the clockspring C2274 pin 5, component side and the upper clockspring connector pin 3, component side.
- Are the resistances less than 5 ohms?
Yes
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.
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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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 seat 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 module.
CLEAR the DTCs. REPEAT the self-test.
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