BMW DTC P1873 – 4-3 Shift Circuit High
DTC P1873 meaning on BMW
DTC P1873 on a BMW indicates a fault in the 4-3 shift circuit, specifically a high voltage condition. This fault code is related to the transmission control module detecting an electrical issue in the circuit responsible for the 4-3 downshift operation.
BMW DTC P1873 symptoms
Symptoms of DTC P1873 on a BMW may include harsh shifting between gears, delayed or erratic shifting, transmission slipping, and in some cases, the transmission may go into a limp mode where it operates in a single gear only.
BMW DTC P1873 causes
The common causes of DTC P1873 on a BMW include faulty wiring or connectors in the 4-3 shift circuit, a malfunctioning transmission control module, or issues with the solenoid or sensors related to the 4-3 downshift operation.
BMW DTC P1873 seriousness
DTC P1873 should be addressed promptly as it can lead to further transmission issues if left unresolved. Ignoring this fault code may result in more severe transmission damage and potentially unsafe driving conditions.
How to diagnose DTC P1873 on BMW
To diagnose DTC P1873 on a BMW, a mechanic would typically start by using a diagnostic scanner to retrieve the fault code and then perform a thorough inspection of the 4-3 shift circuit components, including wiring, connectors, solenoids, and sensors. Testing the transmission control module for proper function may also be necessary.
How to fix DTC P1873 on BMW
Fixing DTC P1873 on a BMW involves addressing the root cause of the high voltage condition in the 4-3 shift circuit. This may include repairing or replacing damaged wiring or connectors, testing and replacing faulty solenoids or sensors, and ensuring the transmission control module is functioning correctly.
How to erase DTC P1873 on BMW
Once the underlying issue causing DTC P1873 on a BMW has been resolved, the fault code can be cleared using a diagnostic scanner. After the repair is completed, the mechanic can erase the fault code, and the transmission should be retested to ensure the issue has been successfully resolved.
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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