LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Dodge and Ram >> 2000 >> Durango 4.7 N, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self Diagnostics >> Diagnostic Tests >> DTC P0136: 1/2 O2 Sensor Heater Circuit Malfunction
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P0136: 1/2 O2 Sensor Heater Circuit Malfunction

NOTE: Test applies only to 4.7L Calif. emission vehicles. For connector terminal ID, see CONNECTOR IDENTIFICATION  . For wiring diagram, see WIRING DIAGRAMS article.
NOTE: 1/2 oxygen sensor heater circuit is monitored when ignition is on and battery voltage is more than 10.4 volts. DTC may be stored in Powertrain Control Module (PCM) if PCM relay control circuit between PCM and oxygen sensor downstream heater relay does not match desired stated. Possible causes are: defective fuse, defective oxygen sensor downstream heater relay, defective PCM, or defective connectors or wiring.
  1. Turn ignition on with engine off. Using scan tool, check for DTCs. If DTC SPECIFIC GOOD TRIP counter is displayed and equal to zero, go to next step. If DTC SPECIFIC GOOD TRIP counter is not displayed and equal to zero, go to step  10 .
  2. Turn ignition off. Check for open or defective fuse No. 11 (10-amp). This is the fuse for oxygen sensor upstream heater relay and oxygen sensor downstream heater relay. Fuse No. 11 is located in junction block on end of driver's side of instrument panel, near door opening. If fuse No. 11 is open or defective, go to next step. If fuse No. 11 is not open or defective, go to step  5 .
  3. Ensure fuse No. 11 is removed from junction block. Remove oxygen sensor downstream heater relay from power distribution center at driver's side front corner of engine compartment, near battery. See Figure . Oxygen sensor downstream heater relay may be referred to as oxygen downstream relay.
  4. Note cavities in power distribution center for oxygen sensor downstream heater relay. See Figure . Using ohmmeter, check resistance between ground and cavity No. 86 (Dark Blue/White wire) in power distribution center for oxygen sensor downstream heater relay. If resistance is 5 ohms or more, replace fuse No. 11 and perform TEST VER-5A  . If resistance is less than 5 ohms, repair short to ground on Dark Blue/White wire between fuse No. 11 in junction block and cavity No. 86 in power distribution center for oxygen sensor downstream heater relay. Replace fuse No. 11 and perform TEST VER-5A  .
  5. Remove oxygen sensor downstream heater relay from power distribution center located at driver's side front corner of engine compartment, near battery. See Figure . Oxygen sensor downstream heater relay may be referred to as oxygen downstream relay.
  6. Note which terminals on oxygen sensor downstream heater relay correspond with cavities in power distribution center. See Figure . Using ohmmeter, check resistance between terminals on oxygen sensor downstream heater relay that correspond with cavities No. 85 and 86 in power distribution center. If resistance is 50-90 ohms, go to next step. If resistance is not 50-90 ohms, replace oxygen sensor downstream heater relay. Perform TEST VER-5A  .
  7. Using ohmmeter, check resistance between cavity No. 17 (Dark Blue/White wire) in junction block for fuse No. 11 and cavity No. 86 (Dark Blue/White wire) in power distribution center for oxygen sensor downstream heater relay. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Blue/White wire between fuse No. 11 in junction block and cavity No. 86 in power distribution center for oxygen sensor downstream heater relay. Perform TEST VER-5A  .
  8. Ensure ignition is off. Disconnect PCM connectors. PCM is located at passenger's side front corner of engine compartment on inner fender panel. Using ohmmeter, check resistance between cavity No. 85 (Orange/Red wire) in power distribution center for oxygen sensor downstream heater relay and terminal No. 9 (Orange/Red wire) on PCM connector C3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Orange/Red wire between PCM and cavity No. 85 in power distribution center for oxygen sensor downstream heater relay. Perform TEST VER-5A  .
  9. Ensure PCM connectors are still disconnected. Using ohmmeter, check resistance between ground and cavity No. 85 (Orange/Red wire) in power distribution center for oxygen sensor downstream heater relay. If resistance is 5 ohms or more, replace PCM. Perform TEST VER-5A  . If resistance is less than 5 ohms, repair short to ground on Orange/Red wire between PCM and cavity No. 85 in power distribution center for oxygen sensor downstream heater relay. Perform TEST VER-5A  .
  10. Start engine and allow engine to idle. Wiggle wiring harness and connectors between PCM, fuse No. 11 (10-amp) and oxygen sensor downstream heater relay while noting DTC SPECIFIC GOOD TRIP counter. PCM is located at passenger's side front corner of engine compartment on inner fender panel. Fuse No. 11 is for oxygen sensor downstream heater relay is located in junction block on end of driver's side of instrument panel, near door opening. Oxygen sensor downstream heater relay is located in power distribution center at driver's side front corner of engine compartment, near battery. See Figure . Oxygen sensor downstream heater relay may be referred to as oxygen downstream relay. If DTC SPECIFIC GOOD TRIP counter does not change to zero while wiggling wiring harness and connectors, go to next step. If DTC SPECIFIC GOOD TRIP counter changes to zero while wiggling wiring harness and connectors, repair wiring or connectors between PCM, fuse No. 11 and oxygen sensor downstream heater relay as necessary. Perform TEST VER-5  .
  11. Shut engine off. Ensure ignition is off. Disconnect PCM connectors. Inspect PCM connectors for corroded, pushed out, miswired or damaged terminals. Inspect wiring harness between PCM, fuse No. 11 and oxygen sensor downstream heater relay for any possible intermittent problems. Also, check for related Technical Service Bulletins (TSBs). If terminals are not corroded, pushed out or damaged and wiring harness is okay, test is complete. If terminals are corroded, pushed out or damaged or wiring harness is damaged, repair as necessary. Perform TEST VER-5  .
scientia non olet · About LEMON Manuals