Diagnostic Procedure

DIAGNOSTIC PROCEDURE

Mass Air Flow Meter Circuit Diagram:

1. Connect the OBDII scan tool or LEXUS hand-held tester, and read value of Mass Air Flow rate.
- If mass air flow rate 0.0 gm/second proceed to step 2.
- If mass air flow rate 271.0 gm/second or more proceed to step 5.
2. Check voltage of Mass Air Flow Meter power source.
- If OK proceed to step 3.
- If not OK check for open in harness and connector between EFI Main Relay and Mass Air Flow Meter.
3. Check voltage between terminal VG and body ground.
- If not OK proceed to step 4.
- If OK check and replace Engine Control Module.
4. Check for open and short in harness and connector between Mass Air Flow Meter and Engine Control Module.
- If OK replace Mass Air Flow Meter.
- If not OK repair or replace harness or connector.
5. Check continuity between terminal and body ground.
- If OK proceed to step 6.
- If not OK check and replace Engine Control Module.
6. Check for open in harness and connector between Mass Air Flow Meter and Engine Control Module.
- If OK replace Mass Air Flow Meter.
- If not OK repair or replace harness or connector.