What does code P1156 mean?

Q: What does code P1156 mean?

O2 Sensor Heater Circuit Low Voltage Bank 2 Sensor 2. P1156 on a BMW means the engine control module has detected that the heater circuit inside the post-catalyst oxygen sensor on bank 2 (the side of the engine that does not contain cylinder 1) is drawing too little voltage, which usually indicates an open circuit, a failed heater element, or a wiring fault. The sensor's heater is responsible for bringing the sensor up to operating temperature quickly so the engine computer can trust its signal for catalyst monitoring and fuel trim corrections.

DTC codes / BMW codes / P1156

P1156 · BMWO2 Sensor Heater Circuit Low Voltage Bank 2 Sensor 2

P1156 on a BMW means the engine control module has detected that the heater circuit inside the post-catalyst oxygen sensor on bank 2 (the side of the engine that does not contain cylinder 1) is drawing too little voltage, which usually indicates an open circuit, a failed heater element, or a wiring fault. The sensor's heater is responsible for bringing the sensor up to operating temperature quickly so the engine computer can trust its signal for catalyst monitoring and fuel trim corrections.

SystemPowertrain

Code typeBMW specific

SeverityLow

Fix difficultyIntermediate

AreaFuel and air metering

Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.