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Home >> Kia >> 1994 >> Sephia LS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Tests >> Code 15: Oxygen Sensor (O2S)
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Code 15: Oxygen Sensor (O2S)

  1. Check O2S connector for poor connection. Clean or repair connector as necessary. If connector is okay, go to next step.
  2. Ensure engine is at normal operating temperature. Disconnect O2S connector. Connect voltmeter between O2S and ground. Start engine and raise engine speed to 3000 RPM until voltmeter indicates .55 volt. Increase and decrease engine speed rapidly several times. When engine speed is increased, voltage should be .5-1.0 volt. When engine speed decreases, voltage should be 0-.4 volt. If voltage is as specified, go to next step. If voltage is not as specified, replace O2S.
  3. Disconnect O2S. Using an ohmmeter, check continuity of Blue/Red wire between O2S connector and terminal No. 20 of ECM C249 (26-pin) connector. If continuity exists, go to next step. If continuity does not exist, repair open Blue/Red wire between O2S connector and ECM connector.
  4. Reconnect O2S connector. Check voltage at terminal No. 20 (Blue/Red wire) of ECM C249 (26-pin) connector while performing the following. Start engine and raise engine speed to 3000 RPM until voltmeter indicates .55 volt. Increase and decrease engine speed rapidly several times. When engine speed is increased, voltage should be .5-1.0 volt. When engine speed decreases, voltage should be 0-.4 volt. If voltage is as specified, replace ECM. If voltage is not as specified, located and repair short in wiring between O2S and ECM connector.
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