Confirmation Engine Racing Pattern
WARNING: This page is about a different car, the 2003 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
- Connect the hand-held tester to the DLC3, or connect the probe of the oscilloscope between terminals OX1A, OX2A, OX1B, OX2B and E2 of ECM connector.
- Start the engine and warm it up with all accessories switched OFF until engine coolant temperature is stable.
- Race the engine at 2500-3000 RPM for about 3 minutes.
- After confirming that the waveform of the heated oxygen sensor bank 1, 2 sensor 1 (OX1A, OX2A), oscillates between zero volts and 1 volt during feedback to the ECM, check waveform of heated oxygen sensor bank 1, 2 sensor 2 (OX1B, OX2B). If there is a malfunction in system, waveform of heated oxygen sensor bank 1, 2 sensor 2 (OX1B, OX2B) is almost the same as heated oxygen sensor bank 1, 2 sensor 1 (OX1A, OX2A). See Fig 1. There are some cases where, even though a malfunction exists, MIL may either light up or not light up.