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P109A – BMW DTC

BMW DTC P109A – H2-Rail Temperature Sensor Circuit Low (Bank 2)

DTC P109A meaning on BMW

DTC P109A indicates a fault with the H2-Rail Temperature Sensor Circuit on Bank 2 in a BMW vehicle. This fault code is specific to the temperature sensor that monitors the fuel rail temperature in the high-pressure fuel system.

BMW DTC P109A symptoms

Symptoms of DTC P109A in a BMW may include:

  • Check Engine Light illuminated
  • Reduced engine performance
  • Potential fuel system issues

BMW DTC P109A causes

Common causes of DTC P109A in a BMW include:

  • Faulty H2-Rail Temperature Sensor
  • Wiring or connector issues in the sensor circuit
  • ECU (Engine Control Unit) malfunction

BMW DTC P109A seriousness

DTC P109A should not be ignored as it can lead to potential engine performance issues and affect fuel system operation in a BMW vehicle. It is recommended to address this fault code promptly to prevent further complications.

How to diagnose DTC P109A on BMW

To diagnose DTC P109A on a BMW, follow these steps:

  1. Use a diagnostic scanner to retrieve the fault code
  2. Inspect the H2-Rail Temperature Sensor and its wiring for any visible damage
  3. Check the sensor’s resistance and compare it to specifications
  4. Test the sensor circuit for continuity and proper voltage

How to fix DTC P109A on BMW

To fix DTC P109A on a BMW, consider the following:

  1. Replace the faulty H2-Rail Temperature Sensor
  2. Repair any damaged wiring or connectors in the sensor circuit
  3. If necessary, address any ECU issues related to the fault code

How to erase DTC P109A on BMW

To erase DTC P109A on a BMW, you can:

  1. Use a diagnostic scanner to clear the fault code
  2. After fixing the underlying issue, reset the Check Engine Light

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

← All BMW Diagnostic Trouble Codes

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