Operation CHARM: Car repair manuals for everyone.
Home >> Jeep Truck >> 2009 >> Wrangler 2WD V6-3.8L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0591

P0591






P0591-SPEED CONTROL SWITCH 2 PERFORMANCE





For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
With the ignition key on.

- Set Condition:
Cruise switch voltage output is not out of range but it does not equal any of the values for any of the button positions. One trip fault.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
1. 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 may result in possible serious or fatal injury.

NOTE: It may be necessary to test drive the vehicle and operate the speed control in order for this DTC to set.

2. With a scan tool, select View DTCs.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. . Intermittent Condition Test

2. SPEED CONTROL SWITCHES
1. Turn the ignition off.
2. Remove the Speed Control Switch from the steering wheel.
3. Measure the resistance across the Speed Control Switch.
4. Monitor the Ohmmeter while pressing each function button on the switch.
5. The following resistance specs are taken between terminals (V72) S/C Signal 2 and (V937) S/C Switch Ground circuit of the Switch when holding the switch button in the following position:
- Not pressing any switch - 20.5 kOhms
- On/Off - 8.87 kOhms
- Set - 0.825 kOhms
- Coast - 0.47 kOhms
- Cancel - 3.92 kOhms
- Resume/Accel - 1.87 kOhms

6. The following resistance specs are taken between terminals (V71) S/C Signal 1 and (V937) S/C Switch Ground circuits of the Switch when holding the switch button in the following position:
- Not pressing any switch - 20.5 kOhms
- On/Off - 0.47 kOhms
- Set - 5.49 kOhms
- Coast - 2.94 kOhms
- Cancel - 1.24 kOhms
- Resume/Accel - 15.4 kOhms

Does the function on the Speed Control Switch have the correct resistance value?

Yes

- Go To 3

No

- Replace the Speed Control Switch that had the incorrect resistance value.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. (V72) S/C SIGNAL 2 CIRCUIT SHORTED TO VOLTAGE




1. Disconnect the C3 PCM harness connector.
2. Ignition on, engine not running.
3. Measure the voltage on the (V72) S/C Signal 2 circuit in the Switch harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (V72) S/C Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. (V72) S/C SIGNAL 2 CIRCUIT OPEN





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 PCM Pinout Box 8815 to perform diagnosis.

1. Turn the ignition off.
2. Measure the resistance of the (V72) S/C Signal 2 circuit from the Switch harness connector to the appropriate terminal of PCM Pinout Box 8815.

Is the resistance below 5.0 Ohms for both measurements?

Yes

- Go To 5

No

- Repair the open in the (V72) S/C Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

5. (V937) S/C SWITCH GROUND OPEN




1. Measure the resistance of the (V937) S/C Switch Ground circuit from the Switch harness connector to the appropriate terminal of PCM Pinout Box 8815.

Is the resistance below 5.0 Ohms for both measurement?

Yes

- Go To 6

No

- Repair the open in the (V937) S/C Switch Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

6. (V72) S/C SIGNAL 2 CIRCUIT SHORTED TO GROUND




1. Measure the resistance between ground and the (V72) S/C Signal 2 circuit in the Switch harness connector.

Is the resistance below 100 Ohms?

Yes

- Repair the short to ground in the (V72) S/C Signal 2 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 7

7. (V72) S/C SIGNAL 2 CIRCUIT SHORTED TO THE (V937) S/C SWITCH GROUND CIRCUIT




1. Measure the resistance between the (V72) S/C Signal 2 circuit and the (V937) S/C Switch Ground circuit in the Switch harness connector.

Is the resistance below 5.0 Ohms?

Yes

- Repair the short between the (V72) S/C Signal 2 circuit and the (V937) S/C Switch Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 8

8. SPEED CONTROL SWITCH VOLTAGE VALUES





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 PCM Pinout Box 8815 and PCM Pinout Box Adapter 8815-1 to perform diagnosis.

1. Using a Voltmeter check the voltage on the (V37) S/C Signal 1 circuit and the (V38) S/C Signal 2 circuit at the appropriate terminals of the PCM Pinout Box 8815.

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 may result in possible serious or fatal injury.

2. Start the engine and allow it to reach normal operating temperature.
3. Monitor the Voltmeter.
4. Allow the engine to idle.
5. With a scan tool, monitor the S/C Switch voltage readings.
6. 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 values?

Yes

- Verify that there is good pin to terminal contact in the Switches and Powertrain Control Module connectors. Replace the Speed Control Switch if no problems were found in the connectors.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 9

9. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Speed Control Switch and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Switch and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

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.

pro multis · About Operation CHARM