DTC Troubleshooting: B1228 (D)
DTC B1228 or DTC indicator D:
 A Short in the Outside Air Temperature Sensor Circuit
  1. Clear the DTC with the HDS.
  1. Turn the ignition switch OFF and then ON (II).
  1. Check for DTCs.
Is DTC B1228 or D indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure.■
  1. Turn the ignition switch OFF.
Is the outside air temperature sensor OK?
YES -
Go to Step 7 .
NO -
Replace the outside air temperature sensor .■
  1. Disconnect the heater control unit 32P connector.
  1. Check for continuity between body ground and the heater control unit 32P connector terminal No. 30.
Is there continuity?
YES -
Repair short to body ground in the wire between the heater control unit and the outside air temperature sensor.■
NO -
Go to Step 9 .
  1. Check for continuity between the heater control unit 32P connector terminals No. 24 and No. 30.
Is there continuity?
YES -
Repair short in the wires between the heater control unit and the outside air temperature sensor.■
NO -
Substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■