DTC P0131: 1/1 O2S VOLTAGE SHORTED TO GROUND Dodge Ram Van B2500

Note. For connector terminal identification, see CONNECTOR IDENTIFICATION . For circuit identification and wiring diagram, see RAM VAN & RAM WAGON wiring diagram in WIRING DIAGRAMS article.

Note. DTC P0131: 1/1 O2S VOLTAGE SHORTED TO GROUND is monitored after ignition is turned off and 1/1 Heated Oxygen Sensor (HO2S) cools down, and after the next time ignition is turned on, provided engine coolant temperature is less than 98°F (36.6°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 1/1 HO2S voltage is less than .156 volt for 28 seconds after engine is subsequently started. Possible causes are: defective 1/1 HO2S, defective PCM, defective connectors or defective wiring.

Note. 1/1 HO2S is located in upstream position.

1. Turn ignition on, with engine off. Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIP COUNTER is displayed and displayed count is "0", go to next step. If DTC SPECIFIC GOOD TRIP COUNTER is not displayed or displayed count is not "0", go to step 4).
2. Turn ignition off. Disconnect 1/1 HO2S connector. Clean and/or repair connector as necessary. Check for short circuit between ground and 1/1 HO2S signal circuit (Tan/White wire). If short circuit exists, go to next step. If short circuit does not exist, replace 1/1 HO2S. Perform TEST VER-5A.
3. Ensure ignition is off. Ensure 1/1 HO2S connector is still disconnected. Disconnect PCM connectors. PCM is located in engine compartment. See PCM LOCATION table under SYSTEM DIAGNOSTICS. Clean and/or repair connectors as necessary. Check for short circuit between engine block (ground) and 1/1 HO2S signal circuit (Tan/White wire). If short circuit to ground exists, repair signal circuit for short to ground as necessary. Perform TEST VER-5A. If short circuit to ground does not exist, repair signal circuit for short to sensor ground circuit (Black/Light Blue wire). Perform TEST VER-5A.
4. Ensure ignition is off. Ensure 1/1 HO2S connector is still disconnected. Clean and/or repair connector as necessary. Wiggle 1/1 HO2S connector and wiring harness between 1/1 HO2S and PCM, while determining if short circuit exists between ground and 1/1 HO2S connector, signal circuit (Tan/White wire). If a short to ground exists, go to next step. If short to ground does not exist, go to step 6).
5. Ensure ignition is off. Ensure 1/1 HO2S and PCM connectors are still disconnected. Clean and/or repair connectors as necessary. Wiggle 1/1 HO2S connector and wiring harness while determining if short circuit exists between ground and 1/1 HO2S signal circuit (Tan/White wire). Repair short to ground in signal circuit as necessary. Perform TEST VER-5A. If short to ground does not exist, repair signal circuit for short to sensor ground circuit (Black/Light Blue wire). Perform TEST VER-5A.
6. Ensure 1/1 HO2S connector is still disconnected. Using scan tool, read and record FREEZE FRAME data. Ensure CAUSED BY DTC matches DTC on DTC screen. If DTC matches, go to next step. If DTC does not match, repair DTC using FREEZE FRAME data.
7. Road test vehicle under conditions in FREEZE FRAME data. Using scan tool, read DTCs. If DTC SPECIFIC GOOD TRIP COUNTER is displayed and displayed count is "0", repeat test. If DTC SPECIFIC GOOD TRIP COUNTER is not displayed or displayed count is not "0", test is complete.