LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Eagle >> 1995 >> Vision ESi >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 3.3L >> Test TC-10A >> Right O2S Stays At Center (DTC 21)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Right O2S Stays At Center (DTC 21)

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION. For wiring diagram, see WIRING DIAGRAMS - 3.3L article in ENGINE PERFORMANCE. After each repair, perform TEST VER-2  .
NOTE: Scan tool displays left oxygen sensor as O2 and right oxygen sensor as O2R.
  1. Start engine. Using scan tool, read right Oxygen Sensor (O2S) voltage. If right O2S voltage is locked on 0.5 volt, go to step 5). If right O2S voltage is not locked on 0.5 volt, go to next step.
  2. Wiggle right O2S wiring while observing scan tool display. If at any time right O2S voltage locks on 0.5 volt, repair harness or connector that caused voltage to lock (open circuit). If right O2S voltage does not lock on 0.5 volt, go to next step.
  3. At this time, the condition required to set trouble code is not present. RIGHT O2S STAYS AT CENTER trouble code sets if right O2S output voltage stays at 0.5 volt for 1.5 minutes with engine temperature more than 170°F (76.6°C) and engine running for 2 minutes. Possible causes are: right O2S circuit open or right O2S failure. Go to next step.
  4. Inspect right O2S wiring and connectors. Repair wiring and connectors as required. If wiring and connectors are okay, see INACTIVE TROUBLE CODE CONDITION  . Test is complete.
  5. If right O2S voltage is locked on 0.5 volt in step 1), disconnect right O2S connector. Using scan tool in ohmmeter mode, check resistance of O2S connector terminal No. 1 (Black/Light Blue wire). If resistance is more than 5 ohms, repair open Black/Light Blue wire. If resistance is less than 5 ohms, go to next step.
  6. Connect a jumper wire between right O2S connector terminal No. 2 (Tan/White wire) and positive battery terminal. Using scan tool, read right O2S voltage. If voltage is more than one volt, replace right O2S. If voltage is less than one volt, go to next step.
  7. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. PCM is located under air cleaner. Leave jumper wire connected. Using scan tool in voltmeter mode, check voltage on PCM connector terminal No. 49 (Tan/White wire). If voltage is more than 10 volts, replace PCM. If voltage is less than 10 volts, repair open Tan/White wire.
scientia non olet · About LEMON Manuals