DTC Troubleshooting: B1225 (A)
DTC B1225 or DTC indicator A:
 An Open in the In-car 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 B1225 or A indicated?
YES -
Go to Step 5 .
NO -
Intermittent failure, check for loose wires or poor connections on the in-car temperature sensor circuit.■
  1. Turn the ignition switch OFF.
Is the in-car temperature sensor OK?
YES -
Go to Step 7 .
NO -
Replace the in-car temperature sensor .■
  1. Disconnect the heater control unit 32P connector.
  1. Check for continuity between the heater control unit 32P connector terminal No. 14 and the in-car temperature sensor 2P connector terminal No. 1.
Is there continuity?
YES -
Go to Step 9 .
NO -
Repair open in the wire between the heater control unit and the in-car temperature sensor.■
  1. Check for continuity between the heater control unit 32P connector terminal No. 24 and the in-car temperature sensor 2P connector terminal No. 2.
Is there continuity?
YES -
Check for loose wires or poor connections at the heater control unit 32P connector and at the in-car temperature sensor 2P connector. If the connections are good, substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit .■
NO -
Repair open in the wire between the heater control unit and the in-car temperature sensor.■