Section 421 (Air Conditioning System - Diagnostics): Pre-Check
- WARNING FOR A/C COMPRESSOR LOCK
If compressor lock occur during A/C switch indicator on the A/C control assembly starts blinking. When this occurs, check for compressor lock (DTC B1422) using diagnosis trouble code check, then proceed to inspect the circuit or the component
Compressor lock sensor circuit. -->(see DTC B1422/22 COMPRESSOR LOCK SENSOR CIRCUIT )
- LIST OF OPERATION METHODS
By operating each of the A/C control switches as shown in Fig 2 , it is possible to enter the diagnosis check mode
- INDICATOR CHECK
- Turn the ignition switch on as pressing the A/C control AUTO switch and R/F.
- Check that all the indicators light up and go off at 1 second intervals 4 times in succession.
HINT:
- After the indicator check is ended, the diagnostic trouble code check begins automatically.
- Press the OFF switch when desiring to cancel the check mode.
- DTC CHECK (SENSOR CHECK)
- Perform an indicator check. After the indicator check is completed, the system enters the DTC check mode automatically.
- Read the DTC displayed on the panel. Refer to the list of DTCs DIAGNOSTIC TROUBLE CODE CHART
when reading the DTCs (DTCs are output at the temperature display.). If the slower display is desired, press the Driver Side Temp. Control Switch and change it to step operation. Each time the Driver Side Temp. Control switch is pressed, the display changes by 1 step.
HINT:
W/ EMV only
- If the buzzer sounds when a DTC is being read, it means the trouble indicated by that DTC continues to occur.
- If the buzzer does not sound when a DTC is being read, it means the trouble indicated by that DTC occurred earlier (such as poor connector contacts, etc.).
- DTC CHECK USING LEXUS HAND-HELD TESTER
- Hook up the LEXUS hand-held tester to the DLC3.
- Read the diagnostic trouble codes by following the prompts on the tester screen.
Please refer to the LEXUS hand-held tester operator's manual for further details.
- CLEARING DTC
- Pull out the ECU-B2 fuse in Passenger Side J/B for 10 sec. or longer to clear the DTC memory.
- After reinserting the fuse, check that the normal code is output.
- CHECK DLC3
The vehicle's ECM uses the ISO 9141-2 communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.
- DATA LIST
HINT:
According to the DATA LIST displayed by LEXUS hand-held tester, you can read the value of the switch, sensor, actuator and so on without parts removal. Reading the DATA LIST as a first step of troubleshooting is one of the method to shorten the labor time.
- Connect the LEXUS hand-held tester to the DLC3.
- Turn the ignition switch ON.
- According to the display on tester, read the "DATA LIST".
- ACTIVE TEST
HINT:
Performing the ACTIVE TEST using LEXUS hand-held tester allows the relay, VSV, actuator and so on to operate without parts removal. Performing the ACTIVE TEST as a first step of troubleshooting is one of the method to shorten the labor time.
It is possible to display the DATA LIST during the ACTIVE TEST.
- ACTUATOR CHECK
- After entering the sensor check mode, press the R/F switch.
- Since each damper, motor and relay automatically operates at 1 second intervals beginning in order from 20 in the temperature display, check the temperature and air flow visually and manually.
If a slower display is desired, press the A/C switch and change it to step operation. Every time the A/C switch is pressed, the display changes by 1 step.
HINT:
- The buzzer sounds when the display trouble code changes.
- Codes are displayed in order from the smaller to the larger numbers.
- To cancel the check mode, press the OFF switch.