BMW 3 Series (incl. M3) Fault Codes

About the 3 Series (incl. M3)

The 3 Series is a compact executive car produced by the German car manufacturer BMW.

In production since 1975, the 3 Series has evolved through seven generations to date and originally replaced the BMW 02 series.

First generations featured the classic BMW two-box grille with sharp angular corners and double circular headlamps. Second generations looked very similar to their predecessors and were available as a four-door sedan, convertible or as an estate version.

1990 saw the first of the third generation models and it was here where the styling became significantly different with a sedan and a hatchback joining the lineup.

It would then go on to be used as the base for the popular compact crossover SUV the X3 like how the larger 5 Series is used as the base for the X5.

By 2018, the new BMW 3 Series had sweeping lines and a much more fluid aesthetic. Showcased at the Paris Motor Show, this new 3 Series kept the station wagon in line up with a new battery electric version joining the family in 2022.

Over its lifetime the BMW 3 Series has won numerous awards, for example, it was named Executive Car of the Year by ‘What Car Magazine’ and has featured in Car and Drivers MAGAZINE Top 10 list more than twenty times.

Impressively, this model was the UK’s best-selling plug-in hybrid car for 2021 and global sales figures exceeded 300,000 units in 1999 and continued to do so up until 2003.

Some fault codes that can appear with this car are:

• P0171 – Either too little fuel or too much oxygen in the exhaust system.
• P0174 – This shows that the air-fuel ratio is too lean.
• P0430 – A poorly functioning catalytic converter.
• P0301 – A misfire of cylinder 1. This can happen for several reasons and a mechanic should be consulted.
• P0138 – The O2 sensor for bank 1 doesn’t have a lower output voltage lower than 1.2 volts.