DTC 66: Pressure Sensor (Inside of VSA Modulator-control Unit) Malfunction

2006 Chevrolet Cobalt SS, 4D Sedan, StandardSECTION DTC 66: Pressure Sensor (Inside of VSA Modulator-control Unit) Malfunction
WARNING: This page is about a different car, the 2011 Honda Insight and 2010 Honda Insight. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM)  ).
  1. Turn the ignition switch to ON (II).
  2. Clear the DTC with the HDS.
  3. Turn the ignition switch to LOCK (0).
  4. Test-drive the vehicle at 19 mph (30 km/h) or more.
    NOTE: Drive the vehicle on the road, not on a lift.
  5. Check for DTCs with the HDS.

    Is DTC 66 indicated? 

    YES  -Go to step 6.

    NO  -The system is OK at this time.

  6. Update the VSA modulator-control unit if it does not have the latest software (see VSA MODULATOR-CONTROL UNIT UPDATE ). If the unit already has the latest software, substitute a known-good VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ).
  7. Turn the ignition switch to LOCK (0).
  8. Test-drive the vehicle at 19 mph (30 km/h) or more.
    NOTE: Drive the vehicle on the road, not on a lift.
  9. Check for DTCs with the HDS.

    Is DTC 66 indicated? 

    YES  -Check for loose terminals in the VSA modulator-control unit 47P connector. If the VSA modulator-control unit was updated, substitute a known-good VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ), then retest. If the VSA modulator-control unit was substituted, Go to step  1.

    NO  -If the VSA modulator-control unit was updated, troubleshooting is complete. If the VSA modulator-control unit was substituted, replace the original VSA modulator-control unit (see VSA MODULATOR-CONTROL UNIT REMOVAL AND INSTALLATION ). If any other DTCs are indicated, go to the indicated DTCs troubleshooting.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.