BMW DTC P1156 – O2 Sensor Heater Circuit Low Voltage (Bank 2 Sensor 2)
DTC P1156 meaning on BMW
The Diagnostic Trouble Code (DTC) P1156 in a BMW indicates an issue with the O2 sensor heater circuit having low voltage on Bank 2 Sensor 2. This means that the heating element in the oxygen sensor located downstream of the catalytic converter on the second bank of cylinders is not receiving sufficient voltage to operate properly.
BMW DTC P1156 symptoms
Symptoms of a DTC P1156 in a BMW may include:
- Check Engine Light (CEL) illuminated on the dashboard
- Poor fuel economy
- Engine running rough or misfiring
- Reduced engine performance
BMW DTC P1156 causes
Common causes of a DTC P1156 in a BMW include:
- Faulty O2 sensor heater circuit
- Corroded or damaged wiring in the O2 sensor circuit
- Defective O2 sensor
- Issues with the engine control module (ECM)
BMW DTC P1156 seriousness
While a DTC P1156 may not cause immediate drivability issues, it can lead to poor engine performance and reduced fuel efficiency. Ignoring this fault code can potentially cause damage to the catalytic converter and other engine components over time.
How to diagnose DTC P1156 on BMW
To diagnose a DTC P1156 on a BMW, a mechanic would typically perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and freeze frame data
- Inspect the wiring and connectors in the O2 sensor heater circuit
- Test the O2 sensor heater for proper resistance and voltage
- Check the ECM for any related faults or issues
How to fix DTC P1156 on BMW
To fix a DTC P1156 on a BMW, the following steps may be taken:
- Replace the faulty O2 sensor if it is determined to be the cause
- Repair or replace any damaged wiring or connectors in the O2 sensor circuit
- Address any issues with the ECM if necessary
- Clear the fault code and perform a test drive to ensure the issue is resolved
How to erase DTC P1156 on BMW
To erase a DTC P1156 on a BMW, the fault code can be cleared using a diagnostic scanner. After the repair has been made and the issue resolved, the mechanic can use the scanner to clear the code from the ECM’s memory. This will turn off the Check Engine Light and reset the system for a fresh start.
Recommended tools & DTC Scanners for BMW
Best Diagnostic App for modern BMWs: BimmerLink
Recommended Bluetooth adapter for Bimmerlink: OBDLink CX
Cable adapter for Bimmerlink: Enet Cable USB Type C
For older BMWs we recommend: Autel AutoLink AL319 (2024 version)
Easy-to-use Multimeter for reliable diagnostics: AstroAI Auto-ranging Multimeter
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