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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> External Pages >> Different car >> Section 7 (Engine Controls - Self-Diagnostics - 2.2L) >> Diagnostic Tests >> DTC P0172: Fuel Trim System Rich >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2002 Isuzu Rodeo Sport and 2002 Isuzu Rodeo. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform ON-BOARD DIAGNOSTIC II SYSTEM CHECK  under SELF-DIAGNOSTIC SYSTEM. After performing OBD-II system check, go to next step.
  2. If any DTCs other than P0172 are set, diagnose other DTCs before proceeding. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  . If no other DTCs are set, go to next step.
  3. Start engine and run until vehicle is operating in closed loop mode. Using scan tool, observe BANK 1 LT FUEL TRIM parameter. If BANK 1 LT FUEL TRIM value is more negative than -14 percent, go to step  5 . If value is not as specified, go to next step.
  4. Using scan tool, read and record FAILURE RECORDS data. Clear DTCs and operate vehicle within conditions noted in FAILURE RECORDS data. Using scan tool, monitor specified DTC parameters while operating vehicle. Continue operating vehicle until DTC P0172 test runs. If scan tool displays DTC P0172 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0172 FAILED THIS IGN, check for intermittent problem. See DIAGNOSTIC AIDS  . If driveability symptom still exists, repair by symptom. See TROUBLE SHOOTING - NO CODES article.
  5. Check air filter element condition. Replace air filter element if necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If air filter element is okay, go to next step.
  6. Check for collapsed or restricted air intake duct. If a problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  7. Start engine. If low or unsteady idle condition exists, go to next step. If idle is okay, go to step  10 .
  8. Using scan tool, observe IDLE AIR CONTROL parameter. If parameter is less than 100 counts, go to step  10 . If parameter is 100 counts or more, go to next step.
  9. Turn ignition off. Check throttle body bore, throttle valve and IAC passages for coking or foreign objects. If problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  10. Check IAC valve for proper operation. See IDLE AIR CONTROL SYSTEM  under MISCELLANEOUS TESTS. If a problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  11. Disconnect vacuum hose from fuel pressure regulator and check it for presence of fuel. If fuel is present, replace fuel pressure regulator. See FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION . After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  12. Turn ignition on. Using scan tool, observe TP ANGLE parameter while slowly depressing accelerator pedal. TP ANGLE parameter should increases steadily from 0 percent at closed throttle to 100 percent at wide open throttle. If parameter increases as specified, go to next step. If parameter does not increase as specified, go to step  17 .
  13. Perform fuel system pressure test. See FUEL PUMP PRESSURE TEST under FUEL SYSTEM in BASIC DIAGNOSTIC PROCEDURES article. If a problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  14. Ensure evaporative emission system is functional. Perform EVAPORATIVE SYSTEMS TEST  under MISCELLANEOUS TESTS. If a problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  15. Perform FUEL INJECTOR BALANCE TEST under FUEL SYSTEM in SYSTEM & COMPONENT TESTING article. If a problem is found, repair as necessary. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If no problem is found, go to next step.
  16. Remove HO2S-1 and check it for silicone (powdery White deposit) contamination. If HO2S is contaminated, replace HO2S. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM. If HO2S is not contaminated, check for intermittent problem. See DIAGNOSTIC AIDS  .
  17. Check and tighten TP sensor mounting screws. If mounting screws are tight, replace TP sensor. See ENGINE SENSORS & SWITCHES in REMOVAL, OVERHAUL & INSTALLATION article. After repair is complete, see VERIFYING VEHICLE REPAIR  under SELF-DIAGNOSTIC SYSTEM.
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