DTC B1497/97: BUS IC Communication Malfunction: Procedure

1. Remove the air conditioning amplifier. Refer to REMOVAL with its connectors still connected.
   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 → See step   4 

OK: Go to next step 

1. Measure the voltage according to the value(s) in the table below.
   Fig 2: Identifying Air Conditioning Amplifier

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard voltage

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

NG → See step   5 

OK → See step   3