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Home >> Dodge and Ram >> 1999 >> Durango 5.9 Z, 4WD, Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Self-Diagnostic Tests >> DTC P0137: 1/2 O2S Volts Shorted To Ground
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DTC P0137: 1/2 O2S Volts Shorted To Ground

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION  . For circuit identification and wiring diagram, see DURANGO wiring diagram in WIRING DIAGRAMS article.
NOTE: DTC P0137: 1/2 O2S VOLTS SHORTED TO GROUND is monitored with engine coolant temperature at more than 170°F (76.7°C) on previous ignition on, after a cold start, engine coolant temperature less than 98°F (36.7°C) and ambient/battery temperature is within 27°F (2.8°C), plus or minus, of engine coolant temperature. DTC may be stored in Powertrain Control Module (PCM) when PCM senses that 1/2 Heated Oxygen Sensor (HO2S) voltage is less than .156 volt for 28 seconds after engine is subsequently started. Possible causes are: defective 1/2 HO2S, defective PCM, defective connectors or defective wiring.
NOTE: 1/2 HO2S is located in downstream position.
  1. If engine is warm, turn engine off for 15 minutes to allow 1/2 HO2S to cool down. Turn ignition on, with engine off. Using scan tool, read 1/2 HO2S voltage. If voltage is less than .16 volt, go to next step. If voltage is .16 volt or more, go to step 8).
  2. Turn ignition off. Disconnect 1/2 HO2S connector. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If connectors and wiring harness are okay, go to next step.
  3. Turn ignition off. If engine is warm, wait 15 minutes to allow 1/2 HO2S to cool down. Ensure 1/2 HO2S connector is still disconnected. Turn ignition on, with engine off. Using scan tool, read 1/2 HO2S voltage. If voltage is less than .16 volt, go to next step. If voltage is .16 volt or more, replace 1/2 HO2S. Perform TEST VER-5A.
  4. Ensure ignition is off. Ensure 1/2 HO2S connector is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Perform TEST VER-5A. If connectors and wiring harness are okay, go to next step.
  5. Ensure ignition is off. Ensure 1/2 HO2S and PCM connectors are still disconnected. Using an ohmmeter, monitor resistance of HO2S signal circuit (Orange/Black wire) between 1/1 HO2S and PCM while wiggling 1/2 HO2S wiring harness. If resistance does not change while wiggling wiring harness, go to next step. If resistance changes while wiggling wiring harness, repair signal circuit for intermittent short to ground. Perform TEST VER-5A.
  6. Ensure ignition is off. Ensure 1/2 HO2S and PCM connectors are still disconnected. Using an ohmmeter, check resistance between ground and PCM connector, 1/2 HO2S signal circuit (Orange/Black wire). If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair signal circuit for short to ground. Perform TEST VER-5A.
  7. At this time, PCM is assumed to be defective. Replace PCM. Perform TEST VER-5A.
    NOTE: Moisture in HO2S connector may cause an intermittent, temporary short condition.
  8. If engine is warm, turn engine off for 15 minutes to allow 1/2 HO2S to cool down. Turn ignition on, with engine off. Wiggle 1/2 HO2S connector and wiring harness while monitoring sensor voltage. If voltage changes while wiggling connector and wiring harness, repair intermittent short to ground in connector or wiring harness where wiggling caused voltage to change. Perform TEST VER-5A. If voltage does not change, test is complete.
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