Toyota Tundra Service Manual: BUS IC Communication Malfunction (B1497/97)

DESCRIPTION

The air conditioning harness connects the air conditioning amplifier and each servo motor. The air conditioning amplifier supplies power and sends operation instructions to each servo motor through the air conditioning harness. Each servo motor sends the damper position information to the air conditioning amplifier.

DTC Code

DTC Detection Condition

Trouble Area

B1497/97

Communication line error or open

  • Air conditioning harness
  • No. 1 damper servo sub-assembly (air mix servo motor)
  • No. 1 damper servo sub-assembly (air outlet servo motor)
  • Air inlet servo motor
  • Air conditioning amplifier
  • Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(a) Select the Active Test, using the Techstream to generate a control command, and then check that the servo motor operates.

Air Conditioner

Tester Display

Test Part

Control Range

Diagnostic Note

Air Mix Servo Targ Pulse (D)

No. 1 damper servo sub-assembly (air mix servo motor) pulse

Min.: 5, Max.: 104

-

Air Outlet Servo Pulse (D)

No. 1 damper servo sub-assembly (air outlet servo motor) pulse

Min.: 9, Max.: 97

-

Air Inlet Damper Targ Pulse

Air inlet damper target pulse

Min.: 7, Max.: 28

-

OK:

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

Result

Result

Proceed to

One of the servo motors is malfunctioning

A

All of the servo motor are malfunctioning

B

B

GO TO STEP 6

A

2.

SYSTEM CHECK

(a) According to the test, proceed to the next step.

Result

Result

Proceed to

Only the No. 1 damper servo sub-assembly (air mix servo motor) is malfunctioning

A

Only the No. 1 damper servo sub-assembly (air outlet servo motor) is malfunctioning

B

Only the air inlet control servo motor is malfunctioning

C

B

GO TO STEP 4

C

GO TO STEP 5

A

3.

CHECK NO. 1 DAMPER SERVO SUB-ASSEMBLY (AIR MIX SERVO MOTOR)

(a) Replace the No. 1 damper servo sub-assembly (air mix servo motor) (See page ).

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.

(b) Check for DTC (See page ).

Result

Result

Proceed to

DTC B1497/97 is not output

A

DTC B1497/97 is output

B

A

END (NO. 1 DAMPER SERVO SUB-ASSEMBLY [AIR MIX SERVO MOTOR] IS DEFECTIVE)

B

GO TO STEP 6

4.

CHECK NO. 1 DAMPER SERVO SUB-ASSEMBLY (AIR OUTLET SERVO MOTOR)

(a) Replace the No. 1 damper servo sub-assembly (air outlet servo motor) (See page ).

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.

(b) Check for DTC (See page ).

Result

Result

Proceed to

DTC B1497/97 is not output

A

DTC B1497/97 is output

B

A

END (NO. 1 DAMPER SERVO SUB-ASSEMBLY [AIR OUTLET SERVO MOTOR] IS DEFECTIVE)

B

GO TO STEP 6

5.

CHECK AIR INLET SERVO MOTOR

(a) Replace the air inlet servo motor (See page ).

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.

(b) Check for DTC (See page ).

Result

Result

Proceed to

DTC B1497/97 is not output

A

DTC B1497/97 is output

B

A

END (AIR INLET SERVO MOTOR IS DEFECTIVE)

B

6.

CHECK AIR CONDITIONING HARNESS

(a) Replace the air conditioning harness.

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.

(b) Check for DTC (See page ).

Result

Result

Proceed to

DTC B1497/97 is not output

A

DTC B1497/97 is output

B

A

END (AIR CONDITIONING HARNESS IS DEFECTIVE)

B

7.

CHECK HARNESS AND CONNECTOR (POWER SOURCE)

(a) Disconnect the J19 air conditioning amplifier connector.

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

Standard voltage:

Tester Connection

Condition

Specified Condition

J19-21 (B) - Body ground

Always

11 to 14 V

OK

REPLACE AIR CONDITIONING AMPLIFIER

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

    Air Outlet Damper Control Servo Motor Circuit (B1443/43)

    Multiplex Communication Circuit (B1499/99)

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