Inspection Procedure

PREPARATION: 

Remove A/C ECU with connectors still connected.

CHECK: 

1. Turn ignition switch to ON.
2. Change the set temperature to activate the cool air bypass damper servomotor and measure voltage between terminals TPBDr and SG of A/C ECU connector each time when the set temperature is changed.

OK: 

Fig 1: Identifying Terminals TPBDR And SG Of A/C ECU Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

As the set temperature increases, the voltage decreases.

1. NG : Go to step 2. 
2. OK : Proceed to next circuit inspection shown on problem symptoms table (See  PROBLEM SYMPTOMS TABLE  ). However, if DTC B1434/34 is displayed, check and replace A/C ECU. 

PREPARATION: 

Remove cool air bypass damper control servomotor (See COOL AIR BY-PASS DAMPER CONTROL SERVOMOTOR ).

CHECK: 

Measure resistance between terminals 1 and 2 of cool air bypass damper control servomotor assembly connector.

OK: 

Resistance: 4.2 - 7.2 kΩ 

CHECK: 

While operating max. cool damper control servomotor, follow the procedure on page COOL AIR BYPASS DAMPER CONTROL SERVOMOTOR CIRCUIT (DRIVER SIDE)  and measure resistance between terminals 2 and 3 of max. cool damper control servomotor assembly connector.

Fig 2: Identifying Cool Air Bypass Damper Position Sensor

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: 

HINT:

As the max cool damper control servomotor moves from the cool side to the hot side, the resistance decreases.

1. NG : Replace cool air bypass damper control servomotor assembly. 
2. OK : Go to next step. 

1. NG : Repair or replace harness or connector. 
2. OK : Check and replace A/C ECU.