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Home >> Toyota >> 2004 >> Matrix Base, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 557 (Air Conditioning System - Diagnostics) >> Circuit Inspection >> DTC 12: Ambient Temperature Sensor Circuit >> Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2003 Toyota Sequoia. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check voltage between terminals TAM and SG-1 of integration control and panel. 

    PREPARATION:

    Remove integration control and panel with connectors still connected.

    CHECK:

    1. Turn ignition switch to ON.
    2. Measure voltage between terminals TAM and SG-1 of integration control and panel connector at each temperature.
    3. Fig 1: Measuring Voltage Between Terminals TAM And SG-1 Of Integration Control And Panel Connector
      G02839042Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK:

    1. Voltage: 
    2. at 25°C (77°F) : 1.35 - 1.75 V 
    3. at 40°C (104°F) : 0.85 - 1.25 V 
    NOTE: As the temperature increases, the voltage decreases.
    1. NG : Go to step 2. 
    2. OK : Proceed to next circuit inspection shown in  PROBLEM SYMPTOMS TABLE  . However, if DTC 12 is displayed, check and replace integration control and panel. 
  2. Check ambient temperature sensor. 

    PREPARATION:

    Disconnect ambient temperature sensor connector.

    CHECK:

    Measure resistance between terminals 1 and 2 of ambient temperature sensor connector at each temperature.

    Fig 2: Identifying Ambient Temperature Sensor Connector Terminal
    G02839043Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK:

    1. Resistance: 
    2. at 25°C (77°F) : 1.6 - 1.8 kΩ 
    3. at 50°C (122°F) : 0.5 - 0.7 kΩ 
    NOTE: As the temperature increases, the resistance decreases.
    NOTE: When installing the ambient temperature sensor, be sure to connect the sensor connector before connecting the battery.
    1. NG : Replace ambient temperature sensor. 
    2. OK : Go To Next Step. 
  3. Check harness and connector between ambient temperature sensor and integration control and panel (See  HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE  ). 
    1. NG : Repair or replace harness or connector. 
    2. OK : Check and replace integration control and panel.