BMW DTC P31B3 – Cylinder 3 H2-Injector High Side Shorted to Coil
DTC P31B3 meaning on BMW
DTC P31B3 for BMW indicates that there is a high side short circuit between the hydrogen injector and the coil in cylinder 3 of the engine.
BMW DTC P31B3 symptoms
Symptoms of DTC P31B3 on a BMW may include rough idling, misfiring, loss of power, decreased fuel efficiency, and potentially an illuminated check engine light on the dashboard.
BMW DTC P31B3 causes
The most common causes of DTC P31B3 on a BMW are a short circuit between the hydrogen injector and the coil in cylinder 3, damaged wiring, or a faulty injector or coil.
BMW DTC P31B3 seriousness
Ignoring DTC P31B3 on a BMW can lead to further engine damage, reduced performance, and potential safety hazards. It is important to address this issue promptly.
How to diagnose DTC P31B3 on BMW
To diagnose DTC P31B3 on a BMW, a mechanic would typically use a diagnostic scanner to retrieve the fault codes and then perform a visual inspection of the wiring harness, injector, and coil in cylinder 3. They may also conduct electrical tests to pinpoint the exact location of the short circuit.
How to fix DTC P31B3 on BMW
Fixing DTC P31B3 on a BMW involves repairing the high side short circuit between the hydrogen injector and the coil in cylinder 3. This may require replacing damaged wiring, the injector, or the coil. Once the issue is resolved, the fault codes should be cleared, and the system should be retested to ensure proper functionality.
How to erase DTC P31B3 on BMW
To erase DTC P31B3 on a BMW, a diagnostic scanner can be used to clear the fault codes stored in the vehicle’s ECU. After the repair has been completed, the codes should be cleared to reset the system and ensure that the issue has been resolved.
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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