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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 40 (Engine Controls - Self-Diagnostics - 2.5) >> Diagnostic Tests >> DTC P1227 Or DTC P1228 >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Nissan Sentra. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Loosen and retighten engine ground bolts. See Figure and Figure . Disconnect APP sensor harness connector. See Fig 1. Measure voltage between ground and APP sensor harness connector terminal No. 1 (Red/Green wire). See Fig 2. If voltage is about 2.5 volts, go to next step. If voltage is not about 2.5 volts, check intermediate connectors in circuit for damage and repair or replace as necessary. If intermediate connectors are OK, repair open or short between APP sensor and ECM and perform DTC CONFIRMATION TEST  to verify repair.
  2. Turn ignition off. Check continuity between engine ground and APP sensor harness connector terminal No. 5 (Green wire). Continuity should exist. Also, check circuit for short to voltage. If problem is found, check intermediate connectors in circuit for damage and repair or replace as necessary. If intermediate connectors are OK, repair open or short between APP sensor and ECM and perform DTC CONFIRMATION TEST  to verify repair. If problem is not found, go to next step.
  3. Disconnect ECM harness connector. See Figure and Figure . Check continuity of Red/Black wire between APP sensor harness connector terminal No. 6 and ECM harness connector terminal No. 76. See Fig 2. Also, check circuits for short to ground and short to voltage. If problem is found, check intermediate connectors in circuit for damage and repair or replace as necessary. If intermediate connectors are OK, repair open or short between APP sensor and ECM and perform DTC CONFIRMATION TEST  to verify repair. If problem is not found, go to next step.
  4. Reconnect all harness connectors. Turn ignition on. Measure voltage between ground and ECM terminals No. 75 (APP sensor No. 1 signal) and No. 76 (APP sensor No. 2 signal) by backprobing, with accelerator pedal in specified positions. See APP SENSOR VOLTAGE . If voltage is as specified, go to next step. If voltage is not as specified, replace APP sensor and perform DTC CONFIRMATION TEST  to verify repair.
    APP SENSOR VOLTAGE

    ECM Terminal No., Sensor No. & Wire Color Accelerator Pedal Position Volts
    75, (APP Sensor No. 1) & (White) Fully Released 0.41-0.71
    Fully Depressed More Than 4.2
    76, (APP Sensor No. 2) & (Red/Black) Fully Released 0.21-0.36
    Fully Depressed More Than 2.1
  5. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
Fig 1: Locating APP Sensor
G00103865Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: Identifying APP Sensor Harness Connector Terminals
G00103866Courtesy of NISSAN MOTOR CO., U.S.A.