LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Suzuki >> 2002 >> Esteem GL, 4D Sedan, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics - 1.6L >> Diagnostic Tests >> DTC P0171 Or DTC P0172 >> Diagnosis & Repair Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnosis & Repair Procedure

  1. If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK  under SYSTEM TESTS.
  2. Using scan tool, check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any DTC other than P0171 or P0172 are present repair those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no other DTCs are set, go to next step.
  3. Start engine and allow it to reach normal operating temperature. Increase engine speed to 2000 RPM for one minute. Allow engine to return to idle. Rev engine 5-6 times repeatedly while monitoring HO2S No. 1 parameter on scan tool. HO2S No. 1 output voltage parameter should vary from less than 0.3 volt to more than 0.6 volt. If parameter is as specified, go to next step. If parameter is not as specified, check HO2S No. 1. Perform diagnosis procedure in DTC P0134: HEATED OXYGEN SENSOR NO. 1 CIRCUIT - NO ACTIVITY DETECTED  .
  4. Check fuel pressure. See FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. Fuel pressure should be 38-44 psi (2.7-3.1 kg/cm2 ) with key on and engine off, and 28-34 psi (2.0-2.4 kg/cm2 ) with engine running at idle. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If no problem is found, go to next step.
  5. Inspect fuel injectors and fuel system circuit. Go to, FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If fuel injectors and fuel system circuit is okay, go to next step.
  6. Ensure engine is cool. Disconnect purge hose from EVAP canister. See Figure . Start engine and allow it to idle. Place finger over end of disconnected hose. If no vacuum is present, go to next step. If vacuum is present, check for EVAP control system malfunction. See FUEL EVAPORATION under EMISSION SYSTEM & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  .
  7. Check MAP sensor operation. Perform diagnosis procedure in DTC P0106: MANIFOLD PRESSURE SENSOR CIRCUIT - PERFORMANCE PROBLEM  . If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If MAP sensor is okay, go to next step.
  8. Check ECT sensor operation. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If ECT sensor operation is okay, go to next step.
  9. Check IAT sensor operation. See ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If IAT sensor operation is okay, go to next step.
  10. Check TP sensor. Perform diagnosis procedure in DTC P0121: THROTTLE POSITION SENSOR CIRCUIT - RANGE/PERFORMANCE PROBLEM  . If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If no problem is found, go to next step.
  11. Disconnect PCV valve from valve cover. Start engine and allow it to idle. Check for vacuum at PCV valve. If vacuum does not exist, disconnect PCV valve from hose. If engine runs rough or stalls, replace PCV valve. If engine does not run rough or stall, check for restriction in PCV hose. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST  . If no problem is found, go to next step.
  12. If PCV system is okay, substitute a known good ECM, and repeat DTC CONFIRMATION TEST  .
scientia non olet · About LEMON Manuals