Particulate Matter Bank 1, Sensor 1 (PM11) Sensor
The PM11 sensor detects the presence of particulates in the filtered exhaust gas. The sensor element consists of comb electrodes of infinite resistance through which exhaust gases pass. Diesel particulates (soot) are primarily carbon and are a good conductor of electricity. When the particulates pass through the electrodes, they allow voltage to pass from one electrode to another, completing a circuit. This change in resistance is detected by the PM11 module and interpreted as soot leakage.
The PM11 sensor also contains a heater element to regenerate the sensor electrodes. The PM11 module activates the heater element, which heats the sensor to greater than 600°C (1112°F) to burn off soot deposits.
The PM11 sensor is located downstream of the diesel particulate filter.
Typical PM11 Sensor