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Home >> Eagle >> 1998 >> Talon Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Self-Diagnostics - With Codes >> DTC Test >> Test TC-112A: Catalyst 1/1 Efficiency Failure
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Test TC-112A: Catalyst 1/1 Efficiency Failure

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article.
  1. Repair any O2S related Diagnostic Trouble Codes (DTCs) before proceeding with this test. If no O2S related DTCs are set, check for any Technical Service Bulletins (TSBs) which may apply. If any TSBs are found to apply, perform TSB action as necessary. If no TSB's apply, go to next step.
  2. CATALYST 1/1 EFFICIENCY FAILURE DTC sets as converter loses its ability to store oxygen. Efficiency drops and oxygen concentration becomes the same downstream as upstream. Output voltage of downstream O2S copies upstream O2S with a time lag seen by the Powertrain Control Module (PCM) between switching of O2S's. Malfunction Indicator Light (MIL) illuminates after 2 trips and remains on. MIL will go out if conditions that set trouble code are not found on 3 subsequent trips. Go to next step.
  3. Possible causes are: faulty catalytic converter, exhaust leaks upstream of catalyst, contaminated fuel, mechanical engine failure or weak O2 sensor with a deteriorated catalyst. Go to next step.
  4. Start engine. Check exhaust system for leaks between engine and downstream O2S. If no exhaust leaks are found, go to next step. If exhaust leaks are found, repair or replace exhaust system parts as necessary. Perform TEST VER-5A .
  5. Check exhaust gas for excessive smoke caused by oil consumption or coolant leaks. If a high oil or coolant consumption condition is not present, go to next step. If a high oil or coolant consumption condition is present, repair engine for mechanical failure and replace catalytic converter. Perform TEST VER-5A .
  6. A newly installed downstream O2S used with an existing (aging) upstream O2S may cause this trouble code to set. If downstream O2S has been replaced within the last 5000 miles, go to next step. If downstream O2S has not been replaced within the last 5000 miles, replace catalytic converter. Perform TEST VER-5A .
  7. If upstream O2S has been replaced within the last 5000 miles, replace catalytic converter. Perform TEST VER-5A . If upstream O2S has not been replaced within the last 5000 miles, replace upstream O2S. Perform TEST VER-5A .
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