Confirmation Engine Racing Pattern

Fig 1: Racing Pattern

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1. Connect the hand-held tester to the DLC3, or connect the probe of the oscilloscope between terminals OX1, OX2 and E1 of the ECM connector.
2. Start engine and warm it up with all accessories switched OFF until water temp, is stable.
3. Race the engine at 2,500 to 3,000 rpm for about 3 minutes.
4. After confirming that the waveforms of the oxygen sensor, bank 1 sensor 1 (OX1), oscillate around 0.5 V during feedback to the ECM, check the waveform of the oxygen sensor, bank 1 sensor 2 (OX2).

HINT:

• If there is a malfunction in the system, the waveform of the oxygen sensor, bank 1 sensor 2 (OX2), is almost the same as that of the oxygen sensor, bank 1 sensor 1 (OX1), on the left.
• There are some cases where, even though a malfunction exists, the MIL may not illuminate.

Fig 2: OX Signal Wave Form

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