P1031 - FAULT CODE - OBD2

P1031 Code failures by brands

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

Description of DTC code P1031

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.

Symptoms of fault code P1031

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

Causes of OBD2 P1031

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.

Possible solutions of the DTC code P1031

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.