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Home >> Lexus >> 2004 >> IS 300 Base, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 51 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0134: Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 1) & DTC P0154: Oxygen Sensor Circuit No Activity Detected (Bank 2 Sensor 1) >> Diagnostic Aids
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Diagnostic Aids

WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. DTC is recorded when air/fuel ratio sensor is malfunctioning although definition is oxygen sensor.
  2. After confirming DTCs, use OBD-II scan tool or hand-held tester to check voltage output of air/fuel ratio sensor (bank 1, 2 sensor 1) from "DIAGNOSIS/ENHANCED OBD-II/DATA LIST/ALL DATA." OBD-II scan tool (excluding hand-held tester) displays 1/5 of air/fuel ratio sensor output voltage which is displayed on hand-held tester.
  3. ECM controls voltage of AFR+, AFL+, AFR- and AFL- terminals of ECM to fixed voltage. Therefore, it is impossible to check air/fuel ratio sensor output voltage without OBD-II scan tool or hand-held tester.
  4. Using a hand-held tester, it is possible to narrow down trouble area by performing ACTIVE TEST of "A/F CONTROL" (oxygen sensor or another can be distinguished).
  5. Connect hand-held tester to DLC3. See Figure.
  6. Turn ignition switch on.
  7. Warm up engine with engine speed at 2500 RPM for approximately 90 seconds.
  8. Perform "A/F CONTROL" at idle condition (press right or left button). Air/fuel ratio sensor and oxygen sensor react simultaneously with increase and decrease of injection volume (+25 percent to rich output: one volt, -12.5 percent to lean output: zero volts). There is a few second delay in sensor 1 (front air/fuel ratio sensor) output. There is about 20 seconds delay in sensor 2 (rear oxygen sensor). See Fig 1.
  9. To display a graph indication, select and push the "YES or NO" button 2 data "AFS B1S1 and O2S B1S2" or "AFS B2S1 and O2S B2S2" and press button "4" after selecting "ACTIVE TEST/AF CONTROL/USER DATA". If DTC P0134 is displayed, check bank 1 sensor 1 circuit. If DTC P0154 is displayed, check bank 2 sensor 1 circuit. Bank No. 1 is also know as right bank (RH).
  10. If the vehicle runs out of fuel, air-fuel ratio is LEAN and DTCs P0134 and P0154 are recorded. MIL then comes on.
  11. Read freeze frame data using hand-held tester or OBD-II scan tool, as freeze frame data records engine conditions when a malfunction is detected. When troubleshooting, it is useful to determine whether vehicle was running or stopped, engine was warmed up or not, air-fuel ratio was lean or rich, etc. at time of malfunction.
Fig 1: Charting Air/Fuel Ratio Sensor & Oxygen Sensor Voltage
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