P1B91 – BMW DTC

BMW DTC P1B91 – 14 Volt Power Module Hybrid Battery System Voltage, Current High

DTC P1B91 meaning on BMW

DTC P1B91 on a BMW refers to a fault with the 14 Volt Power Module Hybrid Battery System Voltage, Current being too high. This diagnostic trouble code indicates that there is an issue with the voltage and current levels in the hybrid battery system, specifically related to the 14-volt power module.

BMW DTC P1B91 symptoms

Symptoms of DTC P1B91 on a BMW may include:

• Check Engine Light illuminated
• Reduced hybrid system performance
• Decreased fuel efficiency
• Hybrid system not engaging properly

BMW DTC P1B91 causes

Common causes of DTC P1B91 on a BMW include:

• Faulty 14 Volt Power Module
• High voltage/current draw from the hybrid battery system
• Issues with the hybrid battery cooling system
• Wiring or connection problems

BMW DTC P1B91 seriousness

The seriousness of DTC P1B91 on a BMW can vary depending on the underlying cause. Ignoring this fault can lead to further damage to the hybrid battery system and potentially affect the overall performance of the vehicle. It is recommended to address this issue promptly to prevent any long-term issues.

How to diagnose DTC P1B91 on BMW

To diagnose DTC P1B91 on a BMW, you can follow these steps:

1. Use a diagnostic scanner to retrieve the fault codes
2. Inspect the 14 Volt Power Module for any visible damage
3. Check the wiring and connections related to the hybrid battery system
4. Perform a voltage/current test on the hybrid battery system

How to fix DTC P1B91 on BMW

To fix DTC P1B91 on a BMW, you may need to:

1. Replace the faulty 14 Volt Power Module
2. Repair any wiring or connection issues
3. Address any high voltage/current draw from the hybrid battery system
4. Ensure proper functioning of the hybrid battery cooling system

How to erase DTC P1B91 on BMW

To erase DTC P1B91 on a BMW, you can:

1. Use a diagnostic scanner to clear the fault codes
2. After fixing the underlying issue, reset the system by disconnecting the battery for a few minutes
3. Ensure that the Check Engine Light is no longer illuminated

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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