LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Infiniti >> 2003 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P2138: Accelerator Pedal Position Sensor Circuit Range/Performance Problem >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. Turn ignition off. Loosen and retighten 2 engine ground bolts. See Figure . Disconnect APP sensor harness connector. Measure voltage between ground and APP sensor harness connector terminals No. 4 (Orange wire) and No. 6 (Red wire). See Figure . If voltage is about 2.5 volts on No. 4 and 5 volts on No. 6, go to step  3 . If voltage is not as specified, go to next step.
  2. Check the following:
    • Check for poor connection at White, 18-pin connector F66 terminal No. 6 (Red wire). See Figure . Connector F66 is located near ECM. See Figure .
    • Check for poor connection at White, 18-pin connector F53 terminal No. 6 (Orange wire). See Figure . Connector F53 is located near ECM. See Figure .
    • Check for open or short between APP sensor and ECM.
    If problem is found, repair as necessary. If problem is not found, go to next step.
  3. Turn ignition off. Check continuity between engine ground and APP sensor harness connector terminal No. 1 (Black/Pink wire). Continuity should exist. Check continuity between engine ground and APP sensor harness connector terminal No. 3 (Black wire). Also, check circuit for short to voltage. If problem is found, go to step  5 . If problem is not found, go to next step.
  4. Check the following:
    • Check for poor connection at White, 18-pin connector F66 terminal No. 6 (Red wire). See Figure . Connector F66 is located near ECM. See Figure .
    • Check for poor connection at joint connector-20 (F71). See Figure .
    • Check for open or short between APP sensor and ECM.
    If problem is found, repair as necessary. If problem is not found, go to next step.
  5. Disconnect ECM harness connector. Check continuity of White/Black wire between APP sensor harness connector terminal No. 5 and ECM harness connector terminal No. 73. Check continuity of White/Black wire between APP sensor harness connector terminal No. 2 and ECM harness connector terminal No. 74. Also, check circuit for short to ground and short to voltage. If problem is found, go to next step. If problem is not found, go to step  6 .
  6. Check the following:
    • Check for poor connection at White, 18-pin connector F66 terminal No. 6 (Red wire). See Figure . Connector F66 is located near ECM. See Figure .
    • Check for open or short between APP sensor and ECM.
    If problem is found, repair as necessary. If problem is not found, go to next step.
  7. Reconnect all harness connectors. Turn ignition switch on. Measure voltage between ground and ECM terminals No. 73 (APP sensor No. 1 signal) and No. 74 (APP sensor No. 2 signal) by backprobing, with accelerator pedal in specified positions. See APP SENSOR VOLTAGE  table in DIAGNOSTIC PROCEDURE under DTC P2122 OR P2123. If voltage is as specified, go to next step. If voltage is not as specified, replace APP sensor.
  8. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
scientia non olet · About LEMON Manuals