LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2000 >> RAV4 Base, AWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 16 (Engine Control System Self-Diagnostics - V6) >> Diagnostic Tests >> DTC P0401: Insufficient Exhaust Gas RECIRCULATION (EGR) Flow Detected >> Diagnosis & Repair (Using Toyota Hand-Held Tester)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair (Using Toyota Hand-Held Tester)

WARNING: This page is about a different car, the 2000 Toyota Camry. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If EGR gas temperature reading is 37.6°F (3.1°C), an open exists in EGR temperature sensor circuit. If temperature reading is 318.7°F (159.3°C), a short exists in EGR temperature sensor circuit.
  1. Connect Toyota hand-held tester to Data Link Connector (DLC) No. 3. See Figure. Start and warm engine to normal operating temperature. Using hand-held tester, read EGR gas temperature. If temperature displayed on hand-held tester is 50-302°F (10-150°C), go to step  5. If temperature displayed on hand-held tester is not 50-302°F (10-150°C), go to next step.
  2. Disconnect EGR temperature sensor harness connector. EGR temperature sensor is mounted on manifold between EGR valve and air intake chamber (built into EGR valve). Connect a jumper wire between EGR temperature sensor harness connector terminals. Turn ignition on. If EGR temperature displayed on hand-held tester is not 318.7°F (159.3°C), remove jumper wire and go to next step. If temperature displayed on hand-held tester is 318.7°F (159.3°C), remove jumper wire. Recheck EGR temperature on hand-held tester. If EGR temperature displayed on hand-held tester is not 37.6°F (3.1°C), go to step  4. If temperature displayed on hand-held tester is 37.6°F (3.1°C), check EGR temperature sensor connector terminals. If problem exists, repair as necessary. If problem does not exist, replace EGR valve.
  3. Turn ignition off. Access ECM behind glove box. Using a jumper wire, backprobe between terminals No. 13 (Green/Yellow wire) and No. 18 (Brown wire) at ECM harness connector E10. See Figure. Turn ignition on. If temperature displayed on hand-held tester is 318.7°F (159.3°C), locate and repair open in wiring between ECM and EGR temperature sensor. If EGR temperature displayed on hand-held tester is not 318.7°F (159.3°C), check ECM connectors. If problem exists, repair as necessary. If problem does not exist, replace ECM.
  4. Remove jumper wire. Disconnect ECM harness connector E10. See Figure. Recheck EGR temperature on hand-held tester. If temperature displayed on hand-held tester is 37.6°F (3.1°C), locate and repair short in wiring between ECM and EGR temperature sensor. If temperature displayed on hand-held tester is not 37.6°F (3.1°C), check ECM connectors. If problem exists, repair as necessary. If problem does not exist, replace ECM.
  5. Check plugged, cracked and disconnected EGR system vacuum hoses. See VACUUM DIAGRAMS article. If problem exists, repair vacuum hoses as necessary. If problem does not exist, go to next step.
  6. Using hand-held tester, select ACTIVE TEST mode. Check operation of EGR VSV when activated by hand-held tester. EGR VSV is located under "V" bank cover on top of engine. With EGR VSV off, air applied to port "E" should flow from port "G". See Fig 1. With EGR VSV on, air applied to port "E" should flow from port "F". If EGR VSV operates as specified, go to step  9. If EGR VSV does not operate as specified, go to next step.
  7. Remove EGR VSV. Measure resistance between EGR VSV terminals (component side). Resistance should be 27-33 ohms at 68°F (20°C). Measure resistance between each terminal and body of EGR VSV (component side). Resistance should be infinite. If resistances are not as specified, replace EGR VSV. If resistances are as specified, go to next step.
  8. Apply battery voltage and ground to EGR VSV terminals. Apply air pressure to EGR VSV port "E". Air should flow from port "F". Remove battery voltage. Apply air pressure to EGR VSV port "E". Air should flow from port "G". If EGR VSV does not operates as specified, replace EGR VSV. If EGR VSV operates as specified, check for open in EGR VSV circuits between engine compartment fuse block and ECM. See WIRING DIAGRAMS article. Repair as necessary.
  9. Disconnect vacuum hose from EGR valve. Start engine and let idle. Apply vacuum to EGR valve. If engine does not run rough or stall, replace EGR valve or clean EGR passage. If engine runs rough or stalls, go to next step.
    10. NOTE: EGR position sensor is an integral part of EGR valve.
  10. Check EGR position sensor and EGR VCV. See EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING - V6 & V8 article. If problem exists, repair as necessary. If problem does not exist, replace ECM.
Fig 1: Identifying EGR VSV Ports
G96C10183Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
scientia non olet · About LEMON Manuals