Thats correct. There are tests that can be done by an experience tech with the proper tools. I will send the steps they do at the shop. The O2 sensors are suppose to be replace regularly so I would think changing them would take care of the issue. Let me know if you have any other concerns. Thanks
|DTC Detecting Condition |
compares the waveform of the oxygen sensor
located before the catalyst with the waveform of the oxygen sensor located after the catalyst to determine whether or not catalyst performance has deteriorated.
Air-fuel ratio feedback compensation keeps the waveform of the oxygen sensor
before the catalyst repeatedly changing back and forth from rich to lean
If the catalyst is functioning normally, the waveform of the oxygen sensor
after the catalyst switches back and forth between rich and lean much more slowly than the waveform of the oxygen sensor before the catalyst.
But when both waveform change at a similar rate, it indicates that catalyst performance has deteriorated. CONFIRMATION ENGINE RACING PATTERN
- Connect the LEXUS hand-held tester to the DLC3, or connect the probe of the oscilloscope between terminals OXL1, OXL2, OXR1, OXR2 and E1 of the ECM connectors.
- Start the engine and warm it up with all the accessories switched OFF until engine coolant temperature is stable.
- Race the engine at 2,500 - 3,000 rpm for about 3 mm .
- After confirming that the waveform of the heated oxygen sensor (bank 1, 2 sensor 1 (OXL1, OXR1)), oscillate around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor (bank 1, 2 sensor 2 (OXL2, OXR2)).
If there is a malfunction in the system, the waveform of the heated oxygen sensor (bank 1, 2 sensor 2 (OXL2, 0XR2)) is almost the same as that of the heated oxygen sensor (bank 1, 2 sensor 1 (OXL1, OXR1)) on the left.
There are some cases where, even though a malfunction exists, the MIL may either light up or not light up.
|Step 1 |
INSPECTION PROCEDURE HINT:
|Steps 2 - 4 |
Read freeze frame data using LEXUS hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.