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Home >> Infiniti >> 2008 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System - DTCS U1000 To P0308 >> DTC P0133, P0153: A/F Sensor 1 >> On Board Diagnosis Logic

On Board Diagnosis Logic

To judge the malfunction of A/F sensor 1, this diagnosis measures response time of the A/F signal computed by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel feedback control constant, and the A/F sensor 1 temperature index. Judgment is based on whether the compensated time (the A/F signal cycling time index) is inordinately long or not.

DTC DETECTING CONDITION CHART

DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P0133
0133 (Bank 1)
Air fuel ratio (A/F) sensor 1 circuit slow response
  • The response of the A/F signal computed by ECM from A/F sensor 1 signal takes more than the specified time.
  • Harness or connectors (The A/F sensor 1 circuit is open or shorted.)
  • A/F sensor 1
  • A/F sensor 1 heater
  • Fuel pressure
  • Fuel injector
  • Intake air leaks
  • Exhaust gas leaks
  • PCV
  • Mass air flow sensor
P0153
0153 (Bank 2)