Toyota CH-R Service Manual: Communication Malfunction (Bus Ic) (B1497)

DESCRIPTION

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

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory
B1497	Communication Malfunction (Bus Ic)	Any of the following conditions is met: Error in communication line Open in communication line	Air conditioning harness assembly No. 1 air conditioning radiator damper servo sub-assembly Air conditioning amplifier assembly	Memorized (10 seconds or more)*

DTC Detection Conditions

		Vehicle Condition
		Pattern 1	Pattern 2
Diagnosis Condition	Ignition switch ON	○	○
Malfunction Status	Error in communication line	○	-
	Open in communication line	-	○
Detection Time		10 seconds or more	10 seconds or more
Number of Trips		1 trip	1 trip

HINT:

DTC will be output when conditions for either of the patterns in the table above are met.

WIRING DIAGRAM

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display	Measurement Item	Control Range	Diagnostic Note
Air Mix Servo Targ Pulse(D)	No. 1 air conditioning radiator damper servo sub-assembly (driver side air mix) pulse	Min.: 128 Max.: 383	Operates between 255 to 347 pulses

Body Electrical > Air Conditioner > Active Test

Tester Display
Air Mix Servo Targ Pulse(D)

OK:

No. 1 air conditioning radiator damper servo motor operates smoothly.

Result	Proceed to
No. 1 air conditioning radiator damper servo motors are malfunctioning	A
No. 1 air conditioning radiator damper servo motors is normal	B

B

GO TO STEP 4

A

2.	INSPECT AIR CONDITIONING HARNESS ASSEMBLY (AIR CONDITIONING AMPLIFIER ASSEMBLY - NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY)

NOTICE:

When inspecting the air conditioning amplifier assembly, do not bring the tester probes too close to each other as a short circuit may occur.

(a) Disconnect the m1 air conditioning amplifier assembly connector.

(b) Disconnect the No. 1 air conditioning radiator damper servo sub-assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
m1-2 (BUS G) - Body ground	Always	Below 1 Ω
m1-3 (BUS) - 2 (LIN)	Always	Below 1 Ω
m1-4 (BUSB) - 1 (+B)	Always	Below 1 Ω

NG

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

OK

3.	INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY

NOTICE:

When inspecting the air conditioning amplifier assembly, do not bring the tester probes too close to each other as a short circuit may occur.

(a) Turn the ignition switch ON.

(b) Connect an oscilloscope to terminals m1-2 (BUS G) and m1-3 (BUS) of the air conditioning amplifier assembly and check the waveform. OK: Waveform is similar to that shown in the illustration. HINT: The waveform varies with the blower speed. Item Content Tool Setting 2 V/DIV., 2 ms./DIV. Vehicle Condition Ignition switch ON.

*a Component with harness connected (Air Conditioning Amplifier Assembly)

OK

REPLACE NO. 1 AIR CONDITIONING RADIATOR DAMPER SERVO SUB-ASSEMBLY

NG

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

4.	CHECK FOR DTC*

(a) Clear the DTCs.

Click here

Body Electrical > Air Conditioner > Clear DTCs

(b) Check for DTCs.

Click here

Body Electrical > Air Conditioner > Trouble Codes

Result	Proceed to
DTCs are not output	A
DTCs are output	B

A

USE SIMULATION METHOD TO CHECK

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY