BMW DTC P1749 – Secondary Pressure Solenoid Communication Error (M52: Internal Transmission Control Module Memory Error)
DTC P1749 meaning on BMW
The DTC P1749 on a BMW indicates a Secondary Pressure Solenoid Communication Error, specifically related to the M52 Internal Transmission Control Module Memory Error. This error code is stored when the transmission control module detects a communication problem with the secondary pressure solenoid.
BMW DTC P1749 symptoms
Symptoms of the DTC P1749 on a BMW may include harsh shifting, transmission slipping, delayed engagement, or the transmission going into limp mode. The Check Engine Light may also be illuminated on the dashboard.
BMW DTC P1749 causes
The primary causes of the DTC P1749 on a BMW are typically related to wiring issues, faulty solenoid, or internal transmission control module problems. Corrosion, loose connections, or damaged wiring can lead to communication errors between the solenoid and the transmission control module.
BMW DTC P1749 seriousness
The DTC P1749 should be addressed promptly as it can lead to drivability issues and potential damage to the transmission if left unresolved. Ignoring this error code may result in further transmission problems and increased repair costs.
How to diagnose DTC P1749 on BMW
To diagnose the DTC P1749 on a BMW, a mechanic would typically start by using a diagnostic scanner to retrieve the fault codes stored in the transmission control module. They would then inspect the wiring harness, connectors, and the secondary pressure solenoid for any visible damage or corrosion. Testing the solenoid’s resistance and checking for proper voltage supply can help pinpoint the issue.
How to fix DTC P1749 on BMW
Fixing the DTC P1749 on a BMW may involve repairing or replacing damaged wiring, connectors, or the secondary pressure solenoid. In some cases, reprogramming or replacing the transmission control module may be necessary to resolve the communication error. It is recommended to follow the manufacturer’s diagnostic and repair procedures to ensure a proper fix.
How to erase DTC P1749 on BMW
Once the underlying issue causing the DTC P1749 on a BMW has been identified and fixed, the fault codes can be cleared using a diagnostic scanner. By clearing the codes, the Check Engine Light should turn off, indicating that the error has been resolved. It is important to verify that the issue has been successfully addressed by performing a test drive and monitoring the transmission’s performance.
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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