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Home >> Mitsubishi >> 1997 >> Eclipse Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.0L - Non-Turbo >> Circuit Tests >> DTC 118 - Fuel System Rich

DTC 118 - Fuel System Rich

NOTE: For terminal identification, see TERMINAL IDENTIFICATION  in SELF-DIAGNOSTICS section. For circuit and wire color identification, see WIRING DIAGRAMS - 2.0L - NON-TURBO article.
  1. Using scan tool, perform SENSOR READ TEST No. 05 (engine coolant temperature). If temperature displayed on scan tool is equal to actual temperature, go to step 5). If temperature displayed is not equal to actual coolant temperature, go to next step.
  2. Disconnect Engine Coolant Temperature (ECT) sensor connector. Check resistance across ECT sensor terminals. Resistance range is between 9000-11,000 ohms at 77°F (25°C) to 600-800 ohms. at 211°F (100°C). If resistance is as specified, go to next step. If resistance is not as specified, replace ECT sensor.
  3. Turn ignition on. Check voltage between ground and ECT sensor connector terminal No. 2. Voltage should be 4.7-5.2 volts. Check continuity between ground and terminal No. 1. If voltage is as specified and continuity exists, check ECT sensor connector. If connector is okay, replace PCM.
  4. If voltage is not as specified or continuity does not exist, check PCM connectors, junction connector and wiring harness between PCM and ECT sensor connector. If wiring and connectors are okay, replace PCM.
  5. Perform SENSOR READ TEST No. 27 (intake air temperature). If temperature displayed on scan tool is equal to actual temperature, go to step 9). If temperature displayed on scan tool is not equal to actual air temperature, go to next step.
  6. Disconnect Intake Air Temperature (IAT) sensor connector. Check resistance across IAT sensor terminals. Resistance range is 9000-11,000 ohms at 77°F (25°C) to 600-800 ohms at 212°F (100C°). If resistance is as specified, go to next step. If resistance is as specified, replace IAT sensor.
  7. Turn ignition on. Check voltage between ground and IAT sensor connector terminal No. 2. Voltage should be 4.7-5.2 volts. Check continuity between ground and terminal No. 1. If voltage is as specified and continuity exists, check IAT sensor connector. If IAT sensor connector is okay, replace PCM.
  8. If voltage is not as specified or continuity does not exist, check PCM connectors, junction connector and wiring harness between PCM and IAT sensor connector. If wiring and connectors are okay, replace PCM.
  9. Perform SENSOR READ TEST No. 11 (manifold absolute pressure reading). Manifold Absolute Pressure (MAP) sensor range is from 30 in. Hg (101 kPa) at 0 ft. (0 m) to 26 in. Hg (88 kPa) at 3937 ft. (1200 m). If scan tool reading is as specified, go to step 12). If scan tool reading is not as specified, go to next step.
  10. Turn ignition on. Check voltage between ground and MAP sensor connector terminal No. 2. Voltage should be 4.7-5.2 volts. Check continuity between ground and terminal No. 1. If voltage is as specified and continuity exists, check MAP sensor connector and wiring harness between PCM and MAP sensor connector. If wiring connector is okay, replace MAP sensor.
  11. If voltage is not as specified or continuity does not exist, check PCM connectors, junction connectors and wiring harness between PCM and MAP sensor connector. If wiring and harness connectors are okay, replace PCM.
  12. Perform SENSOR READ TEST No. 63 (downstream HO2S volts). Drive vehicle in Second gear (M/T) or Low Range (A/T), and accelerate with wide open throttle to 3500 RPM or more. Scan tool reading should alternate between 0-400 millivolts and 600-1000 millivolts, at idle. If voltage is as specified, go to step 16). If voltage is not as specified, go to next step.
  13. Disconnect downstream HO2S connector. Check continuity between downstream HO2S terminals No. 1 and 3. If continuity does not exist, replace downstream HO2S. If continuity exists, go to next step.
  14. Check continuity between ground and downstream HO2S connector terminal No. 2. If continuity exists, go to next step. If continuity does not exist, check wiring harness between PCM and downstream HO2S.
  15. Check downstream HO2S connector, PCM connector and wiring harness between downstream HO2S and PCM. If connectors and wiring are okay, replace PCM.
  16. Perform SENSOR READ TEST No. 02 (upstream HO2S volts). Scan tool reading should be 600-1000 millivolts, when racing engine. If voltage is not as specified, go to step 20). If voltage is as specified, go to next step.
  17. Disconnect upstream HO2S connector. Check continuity between upstream HO2S terminals No. 3 and 4. If continuity does not exist, replace upstream HO2S. If continuity exists, start and warm engine until engine coolant temperature is 176°F (80°C) or more. Connect jumper wires from battery positive to upstream HO2S terminal No. 4 and from battery negative to terminal No. 3 Connect DVOM between upstream HO2S terminal No. 1 and 2.
  18. Monitor upstream HO2S output voltage while repeatedly racing engine. If sensor voltage is not 600-1000 millivolts, replace upstream HO2S. If voltage is 600-1000 millivolts, check continuity between ground and upstream HO2S connector terminal No. 1.
  19. If continuity exists, check upstream HO2S connector, and wiring harness between PCM and upstream HO2S connector. If wiring and connector is okay, replace PCM. If continuity does not exist, check PCM connectors and wiring harness between PCM and upstream HO2S connector.
  20. Repeat SENSOR READ TEST No. 02 (upstream HO2S volts). Scan tool reading should alternate between 0-400 millivolts and 600-1000 millivolts, at idle. If upstream HO2S volts are not as specified, go to next step. If upstream HO2S volts are as specified, check fuel injectors for operation and leakage. Check EVAP control system. See SYSTEM/COMPONENT TESTS - NON-TURBO article.
  21. Check fuel system pressure. See BASIC TESTING - NON-TURBO article. If fuel pressure is okay, and problem exists, check fuel injectors for operation and leakage. Check EVAP control system. See SYSTEM/COMPONENT TESTS - NON-TURBO article. Check for fuel contamination.
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