With LEXUS Hand-Held Tester

MALFUNCTION INDICATOR LAMP CHECK
1. The Malfunction Indicator Lamp (MIL) comes on when the ignition switch is turned ON and the engine is not running.

HINT: If the malfunction indicator lamp does not light up, troubleshoot the combination meter.

2. When the engine is started, the malfunction indicator lamp should go off. If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system.

NOTICE: When the diagnostic system is switched from normal mode to check node, it erases all diagnostic trouble codes and freeze frame data recorded in normal mode. So before switching modes, always check the diagnostic trouble codes and freeze frame data, and note them down.

HOW TO DISPLAY AND READ DIAGNOSTIC TROUBLE CODES (CHECK MODE)
This check mode has high sensing ability to detect malfunctions. Furthermore, the same diagnostic items which are detected in the normal mode can also be detected in the check mode.

1. Initial conditions.
- Battery positive voltage 11 volts or more.
- Throttle valve fully closed.
- Transaxle in PARK position.
- Air conditioning switched off.
2. Turn ignition switch off.
3. Prepare the LEXUS hand-held tester.




4. Connect the LEXUS hand-held tester to data link connector 3 in the fuse box at the lower left of the instrument panel.
5. Turn the ignition switch ON and switch the LEXUS hand-held tester ON.




6. Switch the LEXUS hand-held tester normal mode check mode. (Check that the MIL flashes.)
7. Start the engine. (MIL and O/D OFF indicator light go out after the engine starts.)
8. Simulate the conditions of the malfunction described by the customer.

NOTICE: Leave the ignition switch ON until you have checked the diagnostic trouble codes, etc.

9. After simulating the malfunction conditions, use the LEXUS Hand-Held Tester diagnosis selector to check the diagnostic trouble codes and freeze frame data, etc.

HINT: Take care not to turn the ignition switch OFF, Turning the ignition switch off switches the diagnosis system from check mode to normal mode, so all diagnostic codes, etc. are erased.

10. After checking the diagnostic trouble code, inspect the applicable circuit.




DATA LINK CONNECTOR 3 INSPECTION
The vehicle's ECM uses Variable Pulse Width (VPW) for communication to comply with SAE J1850. The terminal arrangement of DLC 3 complies with SAE J1962 and matches the VPW format.




HINT: If your display shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the cable of the OBD II scan tool or LEXUS hand-held tester to DLC 3, turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool side.
- If communication is normal when the tool is connected to another vehicle, inspect DLC 3 on the original vehicle.
- If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.

HOW TO CHECK FOR INTERMITTENT PROBLEMS
By putting the vehicle's ECM in check mode, 1 trip detection logic is possible instead of 2 trip detection logic and sensitivity to detect open circuits is increased. This makes it easier to detect a intermittent problems.

1. Clear Diagnostic Trouble Codes
For procedure on clearing diagnostic trouble codes, refer to "How to Clear Diagnostic Trouble Codes".

2. Set Check Mode
For procedure on setting the check mode, refer to "How to Display and Read Diagnostic Trouble Codes" given above.

3. Perform A Simulation Test
Using the symptom simulation, apply vibration to and pull lightly on the wire harness, connector or terminals in the circuit indicated by the malfunction code. In this test, if the malfunction indicator lamp lights up, it indicates that the place where the wire harness, connector or terminals being pulled or vibrated has faulty contact. Check that point for loose connection, dirt on the terminals, poor fit or other problems and repair as necessary.

HINT: After canceling out the diagnostic trouble code in memory and setting the check mode, if the malfunction indicator lamp does not go off after the engine is started, check thoroughly for faulty contact, etc., then try the check again. If the malfunction indicator lamp still does not go off, check and replace the ECM.