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Home >> Dodge and Ram >> 1996 >> Caravan Base, 3.3 R >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Controls - Tests W/Codes - 2.4L) >> Trouble Code Tests >> Test TC-103A - Upstream O2 Sensor Heater Failure
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Test TC-103A - Upstream O2 Sensor Heater Failure

WARNING: This page is about a different variant/trim than selected.
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 the upstream oxygen sensor, refer to appropriate test for the specified DTC. If no DTCs exist that are related to the upstream oxygen sensor, go to next step.
  2. Turn ignition on with engine off. Wait 3 minutes and then use scan tool to 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.
  3. If upstream oxygen sensor voltage does not remain at .4-.6 volt, go to next step. If upstream oxygen sensor voltage remains at .4-.6 volt, go to step 5).
  4. Conditions required to set DTC are not present at this time. DTC may be stored in Powertrain Control Module (PCM) if no upstream oxygen sensor voltage signal is received when PCM powers up the upstream oxygen sensor heater. Possible causes are: open heater element circuit, upstream oxygen sensor failure, defective PCM, dirt/moisture or grease inside connector, defective connector terminals/wiring, defective Auto Shutdown (ASD) relay. Stop upstream oxygen sensor heater test. Test complete. Perform TEST VER-5A.
  5. Disconnect connector at upstream oxygen sensor, mounted on the exhaust manifold. Using scan tool in voltmeter mode, check voltage at terminal No. 2 (Dark Green/Orange wire) on wiring harness side of connector for upstream oxygen sensor while still performing upstream oxygen sensor heater test.
  6. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open circuit in Dark Green/Orange wire from Auto Shutdown (ASD) relay. The ASD relay is located in power distribution center at driver's side front corner of engine compartment, near battery. Perform TEST VER-5A.
  7. Stop upstream oxygen sensor heater test. Using external ohmmeter, check resistance of upstream oxygen sensor heater between terminals No. 1 and 2 on oxygen sensor side of connector for upstream oxygen sensor. See Fig 1 .
    Fig 1: Checking Oxygen Sensor Heater Resistance
    G95D35058
  8. If resistance is 4-20 ohms, go to next step. If resistance is not 4-20 ohms, replace upstream oxygen sensor. Perform TEST VER-5A.
  9. Using scan tool ohmmeter mode, check resistance at terminal 1 (Black) on wiring harness side of connector for upstream oxygen sensor. If resistance less than 5 ohms, replace upstream oxygen sensor. Perform TEST VER-5A. If resistance 5 ohms or more, repair open circuit in Black wire and ground. Perform TEST VER-5A.
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