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Home >> Jeep >> 1998 >> Cherokee Classic, 2.5 P >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - Engine Performance >> Self-Diagnostic Tests >> Test TC-118A: Fuel System 1/1 Rich

Test TC-118A: Fuel System 1/1 Rich

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Using scan tool, read DTCs. On AB body, go to next step. On all other bodies, if scan tool displays any HO2S related DTCs, see DTC MESSAGES & CODES  table in DTC TEST and perform appropriate test(s). If no HO2S related DTCs are displayed, go to step 6)  .
  2. If DTC SPECIFIC GOOD TRIPS counter is displayed and displayed count is "0", conditions required to set DTC are not present at this time. Go to step 7)  . If DTC SPECIFIC GOOD TRIPS counter is not displayed or displayed count is not "0", go to next step.
  3. Ensure fuel tank is more than 15 percent full. Turn engine on. Using scan tool, select FUEL LEAN & RICH PRE-TEST. Ensure adaptive memory is updating and LOOP reads CLOSED. If readings are as specified, conditions required to set DTC are not present at this time. Go to step 7)  . If readings are as specified, go to next step.
  4. Turn engine off. Perform TEST NTC-11A: CHECKING OXYGEN SENSOR HEATER . If test fails, perform appropriate repair procedure indicated in test. Test is complete. If test NTC-11A passes, go to next step.
  5. Using scan tool, select FUEL SYS SIMILAR COND WIN and read ADAPTIVE MEMORY FACTOR. If factor is less than -44 percent, perform TEST TC-118B: FUEL SYSTEM 1/1 RICH . If factor is -44 percent or more, test is complete. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .
  6. Check if any Technical Service Bulletins (TSBs) apply to vehicle. If a TSB exists, perform corrective action and perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If no TSBs exist, conditions required to set DTC are not present at this time. Go to next step.
  7. FUEL SYSTEM RICH DTC sets if Powertrain Control Module (PCM) senses fuel system is running too rich on 2 sequential trips. Possible causes are: defective catalytic converter, defective PCM, engine wear, defective fuel injectors, defective MAP sensor, defective upstream Heated Oxygen Sensor (HO2S), defective fuel pressure regulator, or defective connector terminals or connector wires. On AB body, go to step 10)  . On all other bodies, go to next step.
  8. Perform TEST TC-103A: 1/1 O2 SENSOR HEATER FAILURE . If test fails, perform appropriate repair procedure indicated in test. Test is complete. If test passes, go to next step.
  9. Turn engine off. Turn ignition on, engine off. Using scan tool, read LONG TERM ADAPTIVE MEMORY value. If value is not between -20 and -38 percent, condition required to set DTC is no longer present. Test is complete. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES . If value is as specified, perform TEST TC-118B: FUEL SYSTEM 1/1 RICH .
  10. Using scan tool, read and record FREEZE FRAME data. Using scan tool, select FUEL SYS LEAN SIM COND WN. With an assistant, road test vehicle under conditions in FREEZE FRAME data and FUEL SYS LEAN COND WN. If DTC resets, perform TEST TC-118B: FUEL SYSTEM 1/1 RICH . If DTC does not reset, test is complete. Perform TEST VER-5A: ROAD TEST FOR OBD-II TROUBLE CODES .
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