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Home >> Dodge and Ram >> 1996 >> Caravan Base, 2.4 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.4L >> Trouble Code Tests >> Test TC-118A - Fuel System Rich

Test TC-118A - Fuel System Rich

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION DIRECTORY  . For wiring diagram, see WIRING DIAGRAMS - 2.4L article.
  1. Using scan tool, check for stored Diagnostic Trouble Codes (DTCs). If DTCs exist that are related to a rich condition, refer to appropriate test for the specified DTC. If no DTCs exist that are related to a rich condition, go to next step.
  2. This DTC may be stored in Powertrain Control Module (PCM) when PCM determines fuel system is running too rich for at least 2 trips. If this condition exists, Malfunction Indicator Light (MIL) on instrument panel will illuminate and remain on, but goes off if conditions required to set DTC are not found on the following trips.
  3. Possible causes are: defective wiring or connectors, defective catalytic converter, defective intake air temperature sensor, defective EGR valve, defective fuel pump, fuel filter injectors, defective fuel pressure regulator, defective MAP sensor or upstream oxygen sensor, defective PCM or engine mechanical problems. Go to next step.
  4. Turn ignition on with engine off. Using scan tool, monitor upstream oxygen sensor voltage for a few minutes. Once upstream oxygen sensor voltage stabilizes between .4 and .6 volt, using scan tool, actuate upstream oxygen sensor heater test while monitoring upstream oxygen sensor voltage for at least 2 minutes.
  5. If upstream oxygen sensor voltage still remains .4-.6 volt, go to next step. If upstream oxygen sensor voltage does not remain .4-.6 volt, stop upstream oxygen sensor heater test. Perform TEST TC-118B.
  6. Stop upstream oxygen sensor heater test. Using scan tool, check for stored DTCs. If DTC for upstream O2 sensor heater failure exists, perform TEST TC-103A. If no DTC for upstream O2 sensor heater exists, go to next step.
  7. Turn ignition off. Replace upstream oxygen sensor, mounted on exhaust manifold. Start engine and allow engine to idle until engine coolant temperature is at least 180°F (82°C). Allow engine to idle for at least 20 seconds after reaching normal operating temperature.
  8. Using scan tool, monitor upstream oxygen sensor state for at least 10 seconds. If oxygen sensor is switching between lean-center-rich at least 2 times within 10 seconds, go to next step. If oxygen sensor is not switching between lean-center-rich at least 2 times within 10 seconds, turn engine off. Perform TEST TC-118B.
  9. With engine running, using scan tool, read the short and long term adaptive memory values. If long term adaptive memory is less than -20 percent, go to next step. If long term adaptive memory is not less than -20 percent, condition required to set DTC is not present. Test is complete. Perform TEST VER-5A.
  10. Using scan tool, read the purge cel (PURG) values and all purge free cells (PFC) values. Compare the purge cel (PURG) values and the purge free cells (PFC) values.
  11. If the values are not within 6 percent of each other, condition required to set DTC is not present. Test is complete. Perform TEST VER-5A. If the values are within 6 percent of each other, turn ignition off. Perform TEST TC-118B.
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