B1417

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1417/17: Rear Evaporator Temperature Sensor Circuit

DTC B1417/17 - Rear Evaporator Temperature Sensor Circuit

DESCRIPTION

The No. 2 air conditioning harness (rear evaporator temperature sensor) is installed on the evaporator in the rear air conditioning unit to detect the temperature of the cooled air that has passed through the evaporator and to control the rear air conditioner. It sends signals to the air conditioning amplifier. The signals change in accordance with the resistance of the No. 2 air conditioning harness (rear evaporator temperature sensor). As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases. The air conditioning amplifier applies a voltage (5 V) to the No. 2 air conditioning harness (rear evaporator temperature sensor) and reads voltage changes as changes in the resistance of the No. 2 air conditioning harness (rear evaporator temperature sensor). This sensor is used for frost prevention.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (AMBIENT TEMP SENS (REAR))
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON.
(c) Turn the Techstream on.
(d) Enter the following menus: Body Electrical / Air Conditioner / Data List / Ambient Temp Sens (Rear).
(e) According to the display on the Techstream, read the Data List.

Air Conditioner





OK:
The display is as specified in the normal condition.

Result





C -- REPAIR AIR CONDITIONING AMPLIFIER
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.

2. INSPECT NO. 2 AIR CONDITIONING HARNESS (REAR EVAPORATOR TEMPERATURE SENSOR)




(a) Remove the No. 2 air conditioning harness Disassembly.
(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





HINT:
- Touching the thermistor even slightly may change the resistance value. Be sure to hold the connector of the thermistor.
- When measuring, the thermistor temperature must be the same as the ambient temperature.
- As the temperature increases, the resistance decreases (see the graph).

(c) Reinstall the No. 2 air conditioning harness.

NG -- REPAIR NO. 2 AIR CONDITIONING HARNESS
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (NO. 2 AIR CONDITIONING HARNESS - AIR CONDITIONING AMPLIFIER)




(a) Disconnect the P9 No. 2 air conditioning harness connector.
(b) Disconnect the H67 air conditioning amplifier connector.
(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





(d) Reconnect the air conditioning amplifier connector.
(e) Reconnect the No. 2 air conditioning harness connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPAIR AIR CONDITIONING AMPLIFIER