LEMON Manuals: Even more car manuals for everyone
Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 20 (Engine Control System Self-Diagnostics) >> Diagnostic Tests >> DTC P0100: Mass Airflow Meter Circuit >> Diagnosis & Repair

Diagnosis & Repair

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.
  1. Connect Toyota hand-held tester or scan tool to Data Link Connector (DLC) No. 3 at driver's side of instrument panel. See Figure. Turn ignition on and then turn hand-held tester or scan tool on. Start engine and allow engine to idle. Using hand-held tester or scan tool, monitor MAF meter air flow rate. If MAF meter air flow rate is 0.0 gm/sec., go to next step. If MAF meter air flow rate is 271 gm/sec. or more, go to step  5.
  2. Turn ignition off. Disconnect electrical connector at MAF meter. MAF meter is bolted to upper cap on air cleaner assembly and contains a Black 5-pin electrical connector. Turn ignition on. Using voltmeter, check voltage between ground and terminal No. 1 (Black wire) on MAF meter electrical connector. See Fig 1. If voltage is 9-14 volts, go to next step. If voltage is not 9-14 volts, repair open in Black wire between EFI main relay and MAF meter. See WIRING DIAGRAMS article. EFI main relay may also be referred to as EFI relay. EFI main relay is located in fuse/relay box at driver's side front corner of engine compartment.
  3. Turn ignition off. Reinstall electrical connector at MAF meter. Remove glove box for access to ECM with electrical connectors still installed on ECM. See Figure. Ensure A/C switch is in OFF position and shift lever is in Park. Start engine and allow engine to idle. Using voltmeter, check voltage between body ground and terminal No. 10 (Green wire) at ECM electrical connector E8. See Figure. This is the VG terminal on ECM. Voltage should be 1.1-1.5 volts. If voltage is not within specification, go to next step. If voltage is within specification, replace ECM.
  4. Check for open and short in Green wire and electrical connectors between MAF meter and ECM. See WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, replace MAF meter. See AIRFLOW METER under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If wiring harness or electrical connector is defective, repair as necessary.
  5. Turn ignition off. Remove glove box for access to ECM with electrical connectors still installed on ECM. See Figure. Using ohmmeter, check resistance between body ground and terminal No. 19 (Red wire) at ECM electrical connector E8. See Figure. This is the EVG terminal on ECM. If resistance is one ohm or less, go to next step. If resistance is greater than one ohm, replace ECM.
  6. Check for open in wiring harness and electrical connectors between MAF meter and ECM. See WIRING DIAGRAMS article. If wiring harness and electrical connectors are okay, replace MAF meter. See AIRFLOW METER under ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION - 4-CYLINDER article. If wiring harness or electrical connector is defective, repair as necessary.
    Fig 1: Identifying Mass Airflow Meter Electrical Connector Terminals
    G95I31375Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
scientia non olet · About LEMON Manuals