Diagnostic Test

ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
NOTE:
Diagnose and repair any communication DTCs between the SCM and the PCM before proceeding with this test.
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 to set this DTC.
2. With a scan tool, read the Active DTCs.
  Does the scan tool display P1593-SPEED CONTROL SWITCH 1/2 STUCK?
  
  Yes
  - Go To 2.
  No
  - Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
  - Perform the CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Refer to CHECKING FOR AN INTERMITTENT DTC .
STEERING CONTROL MODULE (SCM)
1. Turn the ignition on.
2. With a scan tool, monitor the SCM Cruise Control Switch Status and Cruise Control On/Off Button state.
3. Cycle the Speed Control Switch through each position: On/Off, Set/Coast, Cancel, and Resume/Accel.
  NOTE:
  The Cruise Control Switch Status and Cruise Control On/Off Button state should match each of the actual selections being made with the Speed Control Switch.
  
  Does the scan tool match each of the actual switch selection?
  
  Yes
  - Go To 3.
  No
  - Replace the Speed Control Switch in accordance with the service information.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Steering Column Module (SCM) 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 SCM and PCM connectors.
4. Perform any Technical Service Bulletins that may apply.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the service information.
  - Perform the PCM VERIFICATION TEST. Refer to PCM VERIFICATION TEST .