Inspection Procedure

WARNING: This page is about a different car, the 2002 Toyota Prius. However, it is still accessible from the selected car via links, so may be relevant.

Check voltage between terminals TR and SGTR of A/C amplifier connector.
Preparation:
1. Remove center cluster module control with connectors still connected.
2. Turn the ignition switch ON.
  Check: voltage between terminals TR and SGTR of A/C amplifier connector at each temperature. If OK , voltage at 25 °C (77 °F) : 1.8 - 2.2 V, at 40 °C (104 °F) : 1.2 - 1.6 V.
  
  NOTE: As the temperature increases, the voltage decreases.
  
  Fig 1: Locating A/C Amplifier Terminals TR & SCTR
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Go to step 2.
2. If OK , Proceed to next circuit inspection shown on problem symptoms table. See PROBLEM SYMPTOMS TABLE . However, if DTC 11 is output, check and replace A/C amplifier.
Check room temperature sensor.
PREPARATION: Remove room temperature sensor. See ROOM TEMPERATURE SENSOR .

Check: resistance between terminals 1 and 2 of room temperature sensor connector at each temperature. If OK , at 25 °C (77 °F) : 1.6 - 1.8 kΩ, at 40 °C (104 °F) : 0.5 - 1.7 kΩ.

NOTE: As the temperature increases, the resistance decreases.

Fig 2: Testing Room Temperature Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Replace room temperature sensor.
2. If OK , Go to 3.
Check harness and connector between A/C amplifier and room temperature sensor . See HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION .
1. NG: Repair or replace harness or connector.
2. If OK , Check and replace A/C amplifier.