DTC Troubleshooting: P0638 (40)
DTC P0638:
 ISV Actuator Control Module Range/Performance Problem
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Turn the ignition switch ON (II).
  1. Clear the DTC with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0638 indicated?
YES -
Go to Step 6 .
NO -
Go to Step 4 .
  1. Do the INTAKE SHUTTER VALVE TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0638 indicated?
YES -
Go to Step 6 .
NO -
Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the intake shutter valve and the ECM.■
  1. Turn the ignition switch OFF.
  1. Replace the intake shutter valve.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Do the INTAKE SHUTTER VALVE TEST in the INSPECTION MENU with the HDS.
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P0638 indicated?
YES -
Check for poor connections or loose terminals at the intake shutter valve and the ECM, then go to Step 1 .
NO -
Troubleshooting is complete. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.■