What is the P0040 fault number? What is the description of O2 Sensor Signs Swapped (Bank 2 Sensor 1) failure? How can you fix P0040 fault codes? What are the causes and symptoms of the P0040 fault?
What is the P0040 fault code? What does it stand for?
P0040 is a code that indicates an issue with the upstream oxygen sensor (Bank 1). The powertrain control module (PCM), stores a P0040 code when the voltage signals from the upstream oxygen sensors (located on the engines before the catalytic converters) exceed acceptable limits.
The PCM uses data from oxygen sensors to operate the engine efficiently and adjust the amount of fuel injected. The PCM constantly monitors O2 sensors. This error code can be triggered in extremely rare cases. This error code is used to adjust if fuel is added to the 2nd engine row, but the oxygen sensor from the 1st engine row responds.
This fault code is only visible on vehicles with V-type and Boxer engines with 2 engine rows.
What is the P0040 Fault Code?
- – The oxygen sensor cable is not correctly connected
- – Crossed, damaged, and/or shorted oxygen sensor wiring
- – Defective PCM (rarely)
Note: The most common cause of this fault code is when sensors are connected to the wrong connectors during sensor replacement or removal/installation.
What are the symptoms for P0040 fault code?
- – Continuous illumination, flashing or continuous illumination of the checkengine light
- – Low engine performance
- – Increased fuel consumption
- – Irregular idle speeds and engine vibrations
Note: To prevent further damage, the vehicle’s controller module can switch to safety mode (LimpMode) by entering this code.
How do I fix the P0040 fault code?
- – Attaching sensors to the correct connectors
- Repair and replacement of cables
- – Repair of or replacement of the PCM
How serious is the P0040 fault code?
This code must be immediately diagnosed and fixed. A failure of the PCM or catalytic converter is possible. The vehicle can go into safe mode. You should not start the vehicle before the fault has been fixed.
