P1031 - FAULT CODE - OBD2

P1031 BUICK, CADILLAC, CHEVROLET, DODGE, GMC, OLDSMOBILE, PONTIAC, SATURN: AIR FUEL RATIO SENSOR 1 HEATER CONTROL CIRCUIT LOW BANK 1

Correct fuel injection is based on the readings of conventional oxygen sensors. On the other hand, modern vehicle models add some A/F Sensors (Air/Fuel Ratio Sensors), which guarantee better accuracy in their readings. Although the oxygen sensor and an A/F sensor are similar, the latter has more wires.

They are also known as lambda sensors. A/F sensors are installed in the front exhaust pipe or manifold. They measure how much oxygen is in the exhaust over a wider range, and send that information to the ECM (Engine Control Module). This module takes this data into account and adjusts the air/fuel ratio to keep it within the most optimal level.

The P1031 OBDII diagnostic code setting P1031 means that after completing the On/Off service check of the bank 2 A/F Sensor 1 heater, the ECM detects the voltage of that circuit is excessively below the allowed level.

• Check Engine light ON.
• Unstable operation during idling.
• Lower fuel efficiency.

The reasons for storing the P1031 OBD2 fault code P1031 are:

• Common damage to the A/F Sensor 1 heater circuit wires or connectors.
• Faulty electrical connections at the air/fuel ratio sensor.
• The A/F sensor may be damaged.

To troubleshoot DTC P1031 OBDII, try this:

• Consult the TSBs (Technical Service Bulletins).
• Check the Air/Fuel Ratio Sensor 1 for shortages in any of its wires or connectors. Repair as required.
• Perform voltage tests on the A/F Sensor. Take into account the manufacturer's diagnostic steps. If these checks reveal an out-of-range voltage, make the appropriate adjustments.
• Verify that the resistance of the Air Fuel Ratio Sensor 1 matches the level allowed for proper operation. An out-of-range resistance requires the replacement of the sensor.