How to Troubleshoot the Heating
How to Use the Self-diagnostic Function without the HDS
The heater control unit has a self-diagnostic function. To run the self-diagnostic function, do the following:
  1. Turn the ignition switch to LOCK (0) and then to ON (II).
  1. Press and hold the OFF button, then within 10 seconds press and release the REAR WINDOW DEFOGGER/MIRROR DEFOGGER button five times. Release the OFF button; then the self-diagnostic begins.
    NOTE:
    • The blower motor will run at various speeds regardless of what the panel is displaying.
    • If there is a problem with the system, it will flash 88 and AUTO, 88 and A/C ON, or 88 AUTO and 88 A/C ON, and one or more of the 14 indicator segments (A through P). Refer to checking for DTCs.
    • If there is more than one DTC, they are displayed one at a time in sequence followed by a pause (all the display indicator segments illuminate) between the DTCs.
    • If there are no problems detected, the segments will not illuminate, and the system will appear to be turned off.

Canceling the Self-diagnostic Function

  1. Turn the ignition switch to LOCK (0) to cancel the self-diagnostic function. After completing repair work, run the self-diagnostic function again to make sure that there are no other DTCs.