Toyota 4Runner manuals

Toyota 4Runner: BUS IC Communication Malfunction (B1497/97)

DESCRIPTION

The air conditioning harness assembly connects the No. 1 air conditioning amplifier assembly and each servo motor. The No. 1 air conditioning amplifier assembly supplies power and sends operation instructions to each servo motor through the air conditioning harness assembly. Each servo motor sends the damper position information to the No. 1 air conditioning amplifier assembly.

DTC Code

DTC Detection Condition

Trouble Area

B1497/97

An open circuit or malfunction in the communication line.

  • Air conditioning harness assembly
  • No. 1 air conditioning amplifier assembly

WIRING DIAGRAM


PROCEDURE

1.

CHECK NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

(a) Remove the No. 1 air conditioning amplifier assembly with its connectors still connected (See page ).



(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

z15-2 (BUS G) - Body ground

Always

Below 1 Ω

(c) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

z15-2 (BUS G) - z15-4 (B BUS)

Always

11 to 14 V

z15-2 (BUS G) - z15-3 (BUS)

Ignition switch ON

Pulse generation

Text in Illustration

*a

Component with harness connected

(No. 1 Air Conditioning Amplifier Assembly)

Result

Result

Proceed to

OK (When troubleshooting according to problem symptoms table)

A

OK (When troubleshooting according to the DTC)

B

NG

C


A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


B

REPLACE AIR CONDITIONING HARNESS ASSEMBLY


C

REPLACE NO. 1 AIR CONDITIONING AMPLIFIER ASSEMBLY

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DESCRIPTION The damper servo sub-assembly (driver side air mix damper servo) sends pulse signals to inform the No. 1 air conditioning amplifier assembly of the damper position. The No. 1 air cond ...

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