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Home >> Toyota >> 2001 >> Sienna CE >> Repair and Diagnosis >> External Pages >> Different car >> Section 100 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0300, DTC P0301, DTC P0302, DTC P0303, DTC P0304, DTC P0305, DTC P0306, DTC P0307 Or DTC P0308 >> Diagnosis & Repair (Using OBD-II Scan Tool)

Diagnosis & Repair (Using OBD-II Scan Tool)

WARNING: This page is about a different car, the 2003 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check for DTC output besides P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308. Go to relevant DTC test as necessary. If no other DTCs are present, go to next step.
  2. Check connection of wire harness and connector. Check for disconnection of piping or a break in vacuum hose. Repair as necessary. If okay, go to next step.
  3. Check PCV hose connection. If problem exists, repair as necessary. If problem does not exist, go to next step.
  4. Remove the spark plug. Check the spark plug type and electrode gap. Gap should be 0.039-0.043" (1.0-1.1 mm), with a maximum of .051" (1.3 mm). Replace plug as necessary. Check spark by disconnecting injector connector. Install spark plug to ignition coil. Ground the spark plug. If spark jumps across electrode gap while engine is being cranked, go to step  7. If spark does not jump, go to next step.
  5. Remove the spark plug. Change spark plug. Perform a spark test. Disconnect the injector connector. Install the spark plug to ignition coil. Ground the spark plug. Check that spark jumps across electrode gap while the engine is being cranked. Do not crank engine for more than 5-10 seconds. If spark jumps across electrode gap while engine is being cranked, replace spark plug. If spark does not jump, go to next step.
  6. Check the wire harness between ignition coil and ECM (IF terminal) connectors. Disconnect the I1, I2, I3, I4, I5, I6, I7 or I8 ignition coil connector. Disconnect the ECM E4 connector. See Figure and Figure . Check the continuity between the wire harness side connectors. See ECM/IF SIGNAL TERMINAL CONTINUITY CHECK  table. Disconnect the E2 or E4 ECM connector. See Figure. Check the continuity between the wire harness side connectors. See ECM/IGT SIGNAL TERMINAL CONTINUITY CHECK  table. If all checks are okay, replace ignition coil assembly. If all checks are not okay, repair or replace harness and connector as necessary.
  7. Turn the ignition switch ON. Measure the voltage between the terminals of the E2, E3 and E4 connectors. See Figure. See ECM E2, E3 & E4 CONNECTOR VOLTAGE CHECK  table. If okay, go to step  10. If not okay, go to next step.
  8. Check fuel injectors. Injector volume should be 3.7-4.5 cu. in. per 15 seconds. Difference between each injector should be .6 cu. in. or less. If problem exists, repair as necessary. If problem does not exist, go to next step.
  9. Disconnect the injector connectors. See Figure. Disconnect the E2 and E4 ECM connectors. See Figure. Check the wire harness between the I9, I10, I11, I12, I13, I14, I15 and I16 injector connectors and ECM connectors. Check the continuity between the wire harness side connectors. Check the wire harness between the I9, I10, I11, I12, I13, I14, I15 and I16 injector connectors and IG2 relay. See INJECTOR/ECM CONTINUITY CHECK  table. Remove the INJ fuse from the engine room No. 2 relay block. Check continuity of EFI No. 2 fuse. Disconnect the injector connectors. Remove the IG2 relay from the engine room No. 1 relay block. Check continuity between the wire harness side connectors. See INJECTOR/IG2 RELAY CONTINUITY CHECK  table.
  10. If using scan tool, select the active test mode, and operate fuel pump. If not using hand-held tester, connect positive and negative leads from battery to fuel pump connector. Connect wire to the injector and battery for 15 seconds. See Figure. Measure the injection volume with a graduated cylinder. Test each injector 2-3 times. Injection volume should be 3.7-4.5 cu in. per 15 seconds. Difference between each injector should be 0.6 cu in. or less. If not to specification, repair or replace as necessary. If to specification, go to next step.
  11. Check engine compression. See BASIC DIAGNOSTIC PROCEDURES article. If engine compression is okay, go to next step.
  12. Check valve clearance. See ON-VEHICLE ADJUSTMENTS article. If valve clearance is okay, go to next step.
  13. Check valve timing. Check for loose or jumping teeth of timing belt. Repair as necessary. If okay, go to next step.
  14. Check fuel pressure. See FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. Repair as necessary. If okay, go to next step.
  15. Disconnect the mass airflow sensor connector. Measure the resistance between terminals of mass airflow sensor. See AIRFLOW SENSOR RESISTANCE CHECK  table. See Figure and Figure . Reconnect the mass airflow sensor connector. Turn the ignition switch ON. Measure the voltage between terminals No. 2 and 3 of mass airflow sensor when blowing air into the airflow sensor. Voltage should fluctuate. If okay, go to next step. If not okay, replace mass airflow sensor.
  16. Measure the resistance between the terminals of the coolant temperature sensor. See Figure. Replace coolant temperature sensor as necessary. If okay, check for intermittent problems.
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