P1597 Speed Control Switch Always Low

NAME OF CODE
Speed Control Switches Always Low

WHEN MONITORED
With the ignition key on, and battery voltage greater than 10.4 volts.

SET CONDITION
When switch voltage is less than 4.5 volts for 2 minutes.

THEORY OF OPERATION
A single wire referenced to sensor return ground is used to sense steering wheel mounted switches. Each switch has an associated resistance valve. The switch resistance forms a voltage divider with the PCM's internal pull up resistor to 5 volts. The resistor divider creates a unique voltage at the PCM's input pin thereby allowing multiple switches to be "multiplexed" on a single input.

POSSIBLE CAUSES
- Switch circuit shorted
- PCM failure
- Shorted switch signal circuit
- Shorted switch