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Home >> Infiniti >> 2004 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System >> DTC P1148 & DTC P1168: Closed Loop Control >> Overall Function Check >> With GST
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With GST

  1. Start engine and warm it up to the normal operating temperature.
  2. Turn ignition switch OFF and wait at least 10 seconds.
  3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
  4. Let engine idle for 1 minute.
  5. Set voltmeter probes between ECM terminal 91 [Heated oxygen sensor 1 bank 1 signal] or 92 [Heated oxygen sensor 1 bank 2 signal] and engine ground.
  6. Check the following with engine speed held at 2,000 rpm constant under no-load.
    • The voltage should go above 0.70V at least once.
    • The voltage should go below 0.21V at least once.
  7. If NG, go to DIAGNOSTIC PROCEDURE  .
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