P0591-SPEED CONTROL SWITCH 2 PERFORMANCE
For a complete wiring diagram, refer to the Wiring Information.
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Theory of Operation
The Speed Control Switches are located in the Right Steering Wheel Switch. The Speed Control Switch is a redundant switch consisting of two 5 volt signals sharing a common return circuit. The Right Steering Wheel Switch is hard wired to the Powertrain Control Module (PCM) via the Clockspring pass-through within the Steering Column Control Module (SCCM). The SCCM is located near the top of the steering column below the steering wheel. The SCCM includes the steering column shroud, the Steering Angle Sensor (SAS), the Clockspring, the Multi-function Switch, a Steering Column Power Tilt and Telescope Switch (if equipped), and a trim cover.
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When Monitored:
Continuously with the ignition on.
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Set Condition:
The Powertrain Control Module (PCM) has detected that a non-permissable combination has occurred in the Speed Control Switch.
Possible Causes |
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| RESISTANCE IN THE S/C SIGNAL 2 CIRCUIT |
| SPEED CONTROL SWITCH (RIGHT STEERING WHEEL SWITCH) |
| CLOCKSPRING |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
| 1. | Test drive the vehicle and operate all of the speed control switch positions. |
| 2. | With the scan tool, read DTCs |
Does the scan tool display this DTC as active?
Yes
- Go To 2
No
- Perform the INTERMITTENT DTC diagnostic procedure. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
2. CHECK THE S/C SIGNAL 2 CIRCUIT
| 1. | Turn the ignition off. |
Turn the ignition off disconnect
the 12-volt battery and wait two minutes before proceeding. Failure
to follow these instructions may result in possible serious or fatal
injury.
WARNING:
| 2. | Remove the Driver Air Bag in accordance with the service information (Refer to 10 - Restraints/AIR BAG, Driver/Removal) . |
Do not place an intact non-deployed
airbag face down on a hard surface, the airbag propels into the air
if accidentally deployed. Failure to follow these instructions may
result in possible serious or fatal injury.
WARNING:
| 3. | Back probe the S/C Signal 2 circuit at the Right Steering Wheel Switch harness connector. |
| 4. | Turn the ignition on. |
| 5. | Measure the voltage of the S/C Signal 2 circuit at the Steering Wheel Switch harness connector. |
Is the voltage between 4.9 and 5.1 volts?
Yes
-
Check for spread terminals
at the connector. If the connector and terminals are good, replace
the Right Steering Wheel Switch in accordance with the service information. (Refer to 08 - Electrical/8P - Speed
Control/SWITCH, Speed Control/Removal)
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NOTE: If the P0579 and P0591 DTCs are both present simultaneously, the most likely cause is resistance in the S/C Switch Ground circuit which is shared by both sensors. If both faults are present, check the sensor ground for high resistance before replacing the switch.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Go To 4
3. CHECK THE S/C SIGNAL 2 CIRCUIT
| 1. | Turn the ignition off. |
| 2. | Disconnect the Right Steering Wheel Switch harness connector. |
| 3. | Disconnect the PCM C1 harness connector. |
| 4. | Measure the resistance of the S/C Signal 2 circuit between the Steering Wheel Switch harness connector and the PCM C1 harness connector. |
Is the resistance below 2.0 Ohms?
Yes
- Replace and program the Powertrain Control Module (PCM) in accordance with the service information. (Refer to 08 - Electrical/8E - Electronic Control Modules/MODULE, Powertrain Control - Removal) .
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Go To 4
4. CHECK THE STEERING WHEEL HARNESS
| 1. | Disconnect and remove the Steering Wheel Switch harness from the Steering Wheel Switch and SCM. |
| 2. | Measure the resistance of the S/C Signal 2 circuit in the Steering Wheel Switch harness. |
Is the resistance below 2.0 Ohms?
Yes
- Go To 5
No
- Replace the Steering Wheel harness.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
5. CHECK THE CLOCKSPRING/STEERING CONTROL MODULE
| 1. | Disconnect the Steering Control Module C2 harness connector. |
| 2. | Measure the resistance of the (V38) S/C Signal 2 circuit between the Steering Control Module C2 and the PCM C1 harness connector. |
Is the resistance below 2.0 Ohms?
Yes
- Replace the Steering Control Module in accordance with the service information.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).
No
- Repair the (V38) S/C Signal 2 circuit for an open or high resistance.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).