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Home >> Infiniti >> 2004 >> FX45 >> Repair and Diagnosis >> Engine Performance >> Engine Control System >> DTC P1148 & P1168 Closed Loop Control >> Overall Function Check
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Overall Function Check

Use this procedure to check the overall function of the closed loop control. During this check, a DTC might not be confirmed.

With GST 

  1. Start engine and warm it up to normal operating temperature.
  2. Set voltmeter probes between ECM terminal 16 [HO2S1 (B1) signal] or 35 [HO2S1 (B2) signal] and ground. See Figure .
  3. 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.
  4. If NG, go to DIAGNOSTIC PROCEDURE  .