BMW DTC U1138 – Message Monitoring Idle-Speed Control Valve DPR Overwrite Error (Bank 1)
DTC U1138 meaning on BMW
The Diagnostic Trouble Code (DTC) U1138 for BMW refers to the Message Monitoring Idle-Speed Control Valve DPR Overwrite Error on Bank 1. This error code indicates a problem with the idle-speed control valve, specifically related to the Data Processing Relay (DPR) on Bank 1 of the engine.
BMW DTC U1138 symptoms
Symptoms of the BMW DTC U1138 may include:
- Engine stalling at idle
- Rough idling
- Decreased engine performance
- Check Engine Light (CEL) illuminated on the dashboard
BMW DTC U1138 causes
Possible causes of the BMW DTC U1138 include:
- Faulty idle-speed control valve
- Wiring or connection issues related to the DPR on Bank 1
- Software or programming errors
BMW DTC U1138 seriousness
The DTC U1138 for BMW should be addressed promptly to prevent potential engine performance issues and further damage. Ignoring this error code may lead to drivability problems and increased fuel consumption.
How to diagnose DTC U1138 on BMW
To diagnose the DTC U1138 on a BMW, follow these steps:
- Use a diagnostic scanner to retrieve the fault codes stored in the vehicle’s Engine Control Module (ECM).
- Inspect the idle-speed control valve and its wiring for any visible damage or loose connections.
- Perform a DPR test to check for proper functionality on Bank 1.
- Check for any software updates or reprogramming needed for the ECM.
How to fix DTC U1138 on BMW
To fix the DTC U1138 on a BMW, consider the following:
- Replace the faulty idle-speed control valve if necessary.
- Repair any damaged wiring or connections related to the DPR on Bank 1.
- Update the ECM software to the latest version.
- Clear the fault codes and perform a test drive to ensure the issue is resolved.
How to erase DTC U1138 on BMW
To erase the DTC U1138 on a BMW, use a diagnostic scanner to clear the fault codes stored in the ECM memory. After clearing the codes, perform a test drive to verify that the issue has been resolved and 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
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.