LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Dodge and Ram >> 1997 >> Intrepid ES >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 3.3L >> Self-Diagnostic Tests >> Test TC-125A - Left Downstream O2 Sensor Heater Failure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test TC-125A - Left Downstream O2 Sensor Heater Failure

NOTE: For connector terminal ID, see CONNECTOR IDENTIFICATION DIRECTORY  table. For wiring diagram, see WIRING DIAGRAMS - 3.3L article.
NOTE: Vehicle is equipped with left and right downstream O2 sensor.
  1. Turn ignition on. Using scan tool, monitor left downstream O2 sensor voltage for a few minutes. Wait for voltage reading to stabilize between .4 and .6 volt. Using scan tool in actuator test mode, perform O2 sensor heater test. Monitor left downstream O2 sensor voltage for 2 minutes. If voltage is still between .4 and .6 volt, go to step  3. If voltage is not between .4 and .6 volt, go to next step.
  2. At this time, condition required to set this code is not present. Code will set when no sensor output signal is received when PCM powers up sensor heater. Possible causes are: open heater element circuit, O2 sensor failure, PCM failure, dirt/moisture/grease inside connector, O2 sensor heater wires or ASD relay failure. Stop all actuator tests. Test is complete. Perform TEST VER-5A .
  3. With scan tool still actuating sensor O2 heater test, disconnect left downstream O2 sensor connector. Inspect connectors. If any terminal is corroded, damaged, pushed out or miswired, repair as necessary. Perform TEST VER-5A . If connectors are okay, go to next step.
  4. With scan tool still actuating sensor O2 heater test, measure voltage between ground and ASD relay output circuit at left downstream O2 sensor harness connector terminal No. 3 (Dark Green/Orange wire). If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in ASD relay output circuit between left downstream O2 sensor and splice located near left downstream O2 sensor. Perform TEST VER-5A .
  5. Stop actuator test. Using an ohmmeter, measure resistance between 2 White wires at left downstream O2 sensor connector (component side). If resistance is 4-7 ohms, go to next step. If resistance is not 4-7 ohms, replace left downstream O2 sensor. Perform TEST VER-5A .
  6. Using an ohmmeter, measure resistance between ground and sensor ground circuit at left downstream O2 sensor harness connector terminal No. 1 (Black/Light Blue wire). If resistance is less than 5 ohms, replace left downstream O2 sensor. Perform TEST VER-5A . If resistance is 5 ohms or more, repair open in sensor ground circuit. Perform TEST VER-5A .
scientia non olet · About LEMON Manuals