Catalytic Converter Temperature Monitoring

The M5 is equipped with an exhaust temperature sensor at the catalyst for cylinder bank 5-8. The sensor is a PTC resistor which allows the MS S52 to monitor the catalyst temperature. This input is considered for mixture control by the MS S52 for catalyst efficiency. In the event of an overheat situation, the ECM will illuminate the Malfunction Indicator Light (MIL) and set a fault code. Under certain load conditions, the fuel mixture is enriched to aid in cooling down the catalytic converters.

Fig 1: Locating Catalytic Converter Temperature Sensor

Courtesy of BMW OF NORTH AMERICA, INC.

Fig 2: Catalytic Converter Temperature Monitoring Check Sheet

Courtesy of BMW OF NORTH AMERICA, INC.