P0580
P0580-SPEED CONTROL SWITCH 1 CIRCUIT LOW
For a complete wiring diagram refer to Diagrams/Electrical.
- When Monitored:
With the ignition key on.
- Set Condition:
Speed control switch input No.1 is below the minimum acceptable voltage at the PCM. One trip fault.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. ACTIVE DTC
NOTE: Do not press the Speed Control Switch button.
Start the engine and allow it to idle for at least 60 seconds.
WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.
With a scan tool, select View DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
2. SPEED CONTROL SWITCH
Turn the ignition off.
Remove and disconnect the Speed Control Switch from the steering wheel.
Measure the resistance across each Speed Control Switch.
Monitor the ohmmeter while pressing each function button for each switch.
The following resistance specs are taken between terminals (V71) S/C Signal 1 circuit and (V937) S/C Return circuit of the Switch when holding the switch button in the following positions.
Not pressing any switch - 20.5k ohms
On/Off - 0.47k ohms
Set - 5.49k ohms
Coast - 2.94k ohms
Cancel - 1.24k ohms
Resume/Accel - 15.4k ohms
Does the function on the Speed Control Switch have the correct resistance value?
Yes
- Go To 3
No
- Replace the Speed Control Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
3. SPEED CONTROL SWITCH
With the scan tool, monitor the Speed Control Switch voltage.
Disconnect the Speed Control Switch harness connector.
NOTE: The sensor voltage should be approximately 5.0 volts(plus or minus .1 volt) with the connector disconnected.
Does the scan tool display the voltage as described above?
Yes
- Replace the Speed Control Resume/Accel Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 4
4. (V71) S/C SIGNAL 1 CIRCUIT SHORTED TO THE (V937) S/C RETURN CIRCUIT
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between the (V937) S/C Return circuit and the (V71) S/C Signal 1 circuit at the S/C Switch harness connector.
Is the resistance below 5.0 ohms?
Yes
- Repair the short between the (V71) S/C Signal 1 circuit and the (V937) S/C Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 5
5. (V71) S/C SIGNAL 1 CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (V71) S/C Signal 1 circuit in the S/C Switch harness connector.
To help determine the location of a short, disconnect the Steering Column Control Module C2 and C5 harness connectors and see if the short goes away.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (V71) S/C Signal 1 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 6
6. EXCESSIVE RESISTANCE IN THE (V71) S/C SIGNAL 1 CIRCUIT
CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.
Measure the resistance of the (V71) S/C Signal 1 circuits from both Speed Control harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 7
No
- Repair the excessive resistance in the (V71) S/C 1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
7. SPEED CONTROL SWITCH VOLTAGE VALUES
Allow the engine to idle.
With a scan tool, monitor the S/C Switch voltage readings.
Take these same voltage measurements with a voltmeter by back probing the (V71) S/C Signal 1 circuit at the switch.
Compare the voltage readings on the voltmeter to what the scan tool displayed.
Are the voltage readings out of the listed specification and is there less than a 0.2 of a volt difference between the voltmeter switch values and the scan tool switch value?
Yes
- Replace the Speed Control Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Go To 8
8. PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
No
- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test