P1A91 – BMW DTC

BMW DTC P1A91 – DC/DC Converter Internal DC Link Discharge – Discharge Time 2 Too Long

DTC P1A91 meaning on BMW

DTC P1A91 on a BMW refers to the DC/DC Converter Internal DC Link Discharge – Discharge Time 2 Too Long. This diagnostic trouble code indicates that the DC/DC converter’s internal DC link discharge time has exceeded the specified limit.

BMW DTC P1A91 symptoms

Symptoms of DTC P1A91 on a BMW may include:

• Check Engine Light (MIL) illuminated
• Reduced power or performance
• Possible hybrid system warning light

BMW DTC P1A91 causes

Common causes of DTC P1A91 on a BMW include:

• Internal DC/DC converter failure
• Issues with the high-voltage battery
• Wiring or connection problems

BMW DTC P1A91 seriousness

The seriousness of DTC P1A91 on a BMW can vary. While it may not always result in immediate drivability issues, prolonged exposure to this fault code can lead to further damage to the hybrid system components.

How to diagnose DTC P1A91 on BMW

To diagnose DTC P1A91 on a BMW, a comprehensive diagnostic scan tool capable of reading hybrid system codes is required. The following steps can help in the diagnosis:

1. Retrieve the fault codes and freeze frame data
2. Inspect the high-voltage battery and connections
3. Check the DC/DC converter for proper operation
4. Perform a system voltage test

How to fix DTC P1A91 on BMW

Fixing DTC P1A91 on a BMW may involve the following steps:

1. Repair or replace the faulty DC/DC converter
2. Address any issues with the high-voltage battery
3. Repair wiring or connection problems
4. Clear the fault codes and perform a test drive

How to erase DTC P1A91 on BMW

To erase DTC P1A91 on a BMW, follow these steps:

1. Use a diagnostic scan tool to clear the fault codes
2. Perform a battery reset procedure if necessary
3. Ensure the issue has been resolved before clearing the codes

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

Some of the links on this page may be affiliate links, which means we may earn a small commission if you make a purchase. This helps us keep our DTC database up to date and provide valuable content for free. We only recommend products that we have tested and believe to be the best in their class.