DTC B1497/97: BUS IC Communication Malfunction: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch on (IG) and turn the Techstream main switch on.
3. Check the operation by referring to the table below.
   ACTIVE TEST / AIR CONDITIONER
   
   

   Tester Display	Test Part	Control Range	Diagnostic Note
   A/O Servo Pulse (RrD)*1	Rear air outlet control servo motor pulse	Min.: 7, Max.: 82	-
   Air Mix Servo Targ Pulse (D)	Air mix control servo motor pulse	Min.: 7, Max.: 105	-
   Air Outlet Servo Pulse (D)	Air outlet control servo motor pulse	Min.: 8, Max.: 97	-
   Air Inlet Damper Targ Pulse	Air inlet damper target pulse	Min.: 7, Max.: 28	-
   Air Mix Servo Targ Pulse (R)*1	Rear air mix control servo motor pulse	Min.: 9, Max.: 54	-

   *1: w/ Rear Air Conditioning

   OK

   Arm of the damper servo motor selected in the Active Test moves smoothly

4. According to the test, proceed to the next step.

   Result

   Result	Proceed to
   One of the front air conditioner control servo motors is malfunctioning	A
   All of the front air conditioner control servo motors are malfunctioning	B
   One of the rear air conditioner control servo motors is malfunctioning	C
   All of the rear air conditioner control servo motors are malfunctioning	D

B → See step   6 

C → See step   7 

D → See step   10 

A: Go to next step 

1. According to the test, proceed to the next step.

   Result

   Result	Proceed to
   Only the air mix control servo motor is malfunctioning	A
   Only the air inlet control servo motor is malfunctioning	B
   Only the air outlet control servo motor is malfunctioning	C

B → See step   4 

C → See step   5 

A: Go to next step 

1. Replace the air mix control servo motor. Refer to REMOVAL .

   HINT: 

   Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   6 

A → END 

1. Replace the air inlet control servo motor. Refer to REMOVAL .

   HINT: 

   Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   6 

A → END 

1. Replace the air outlet control servo motor. Refer to REMOVAL .

   HINT: 

   Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   6 

A → END 

1. Replace the air conditioning harness. Refer to DISASSEMBLY .

   HINT: 

   Since the air conditioning harness cannot be inspected while it is removed from the vehicle, replace the air conditioning harness with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   12 

A → END 

1. According to the test, proceed to the next step.

   Result

   Result	Proceed to
   Only the rear air mix control servo motor is malfunctioning	A
   Only the rear air outlet control servo motor is malfunctioning	B

B → See step   9 

A: Go to next step 

1. Replace the rear air mix control servo motor. Refer to REMOVAL .

   HINT: 

   Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   10 

A → END 

1. Replace the air outlet control servo motor. Refer to REMOVAL .

   HINT: 

   Since the servo motor cannot be inspected while it is removed from the vehicle, replace the servo motor with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   10 

A → END 

1. Disconnect the rear air conditioning harness connector.
   Fig 1: Checking Harness And Connector (Air Conditioning Amplifier - Rear Air Conditioning Harness)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the air conditioning amplifier connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   D38-23 (RBBU) - N12-4 (RBBU)	Always	Below 1 Ω
   D38-1 (RBUS) - N12-3 (RBUS)	Always	Below 1 Ω
   D38-21 (RBUG) - N12-2 (RBUG)	Always	Below 1 Ω
   D38-23 (RBBU) - Body ground	Always	10 kΩ or higher
   D38-1 (RBUS) - Body ground	Always	10 kΩ or higher
   D38-21 (RBUG) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK: Go to next step 

1. Replace the rear air conditioning harness. Refer to DISASSEMBLY .

   HINT: 

   Since the rear air conditioning harness cannot be inspected while it is removed from the vehicle, replace the rear air conditioning harness with a new or a known good one and check that the condition returns to normal.

2. Check for the DTC.

   Result

   Result	Proceed to
   DTC B1497 is not output	A
   DTC B1497 is output	B

B → See step   12 

A → END 

1. Disconnect the air conditioning amplifier connector.
   Fig 2: Checking Harness And Connector (Power Source)

   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
   D37-21 (B) - Body ground	Always	11 to 14 V
   D38-24 (+B2) - Body ground	Always	11 to 14 V

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   13