DTC B1497/97: BUS IC Communication Malfunction: Procedure

1. Remove the air conditioning amplifier with its connectors still connected, refer to REMOVAL - Step 6 .
   Fig 1: Identifying Air Conditioning Amplifier

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance according to the value(s) in the table below.

   Standard resistance

   Tester Connection	Condition	Specified Condition
   z17-2 (BUS G) - Body ground	Always	Below 1 Ω

NG → CHECK GROUND LINE AND AIR CONDITIONING AMPLIFIER 

OK: Go to next step 

1. Remove the air conditioning amplifier with its connectors still connected, refer to REMOVAL - Step 6 .
   Fig 2: Identifying Air Conditioning Amplifier

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the voltage according to the value(s) in the table below.

   Standard voltage

   Tester Connection	Condition	Specified Condition
   z17-2 (BUS G) - z17-4 (B BUS)	Ignition switch on (IG)	11 to 14 V
   z17-2 (BUS G) - z17-3 (BUS)	Ignition switch on (IG)	Pulse generation

NG → See step   3 

OK → REPLACE AIR CONDITIONING HARNESS ASSEMBLY