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Home >> Suzuki >> 2001 >> Esteem GL, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - Esteem 1.8L >> Diagnostic Tests >> DTC P0121: Poor Throttle Position Sensor Performance >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Perform DTC CONFIRMATION TEST  . If DTC P0121 is set, go to next step. If DTC P0121 is not set, problem is intermittent. System is okay at this time. See TROUBLE SHOOTING - NO CODES article.
  2. Check TP sensor operation. See SYSTEM & COMPONENT TESTING article. If TP sensor is okay, go to next step. If TP sensor is not okay, go to step  4 .
  3. Check intake system for plugging and vacuum leaks. Repair as necessary. If intake system is okay, turn ignition off. Disconnect ECM 28-pin connector C20. Check for poor terminal contact at ECM 28-pin connector C20. If poor terminal contact is found, repair as necessary and go to DTC CONFIRMATION TEST  . If terminal contact is okay, replace ECM and go to DTC CONFIRMATION TEST  .
  4. Adjust TP sensor. See THROTTLE POSITION (TP) SENSOR in ON-VEHICLE ADJUSTMENTS article. Recheck TP sensor operation. If TP sensor operation is still not okay, go to next step.
  5. Turn ignition off. Disconnect TP sensor connector. Check for poor terminal contact at TP sensor connector. If poor terminal contact is found, repair as necessary and go to DTC CONFIRMATION TEST  . If terminal contact is okay, measure resistance between TP sensor terminal No. 1 (Orange wire) and No. 3 (Pink/Green wire). Resistance should be 4-6 k/ohms. Go to next step.
  6. Also measure resistance between TP sensor terminal No. 1 (Orange wire) and No. 2 (Gray wire). Resistance should be 0.1-6.5 k/ohms (measurement will vary according to throttle valve opening). If readings are not as specified, replace TP sensor and go to DTC CONFIRMATION TEST  . If readings are as specified, check for high resistance in circuits between TP sensor and ECM 28-pin connector C20. If circuits are okay, replace ECM and go to DTC CONFIRMATION TEST  .
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