BMW DTC P18D4 – Ratio Monitoring Shift From Gear 4
DTC P18D4 meaning on BMW
The DTC P18D4 code on a BMW indicates a ¨Ratio Monitoring Shift From Gear 4¨ fault. This fault code is specific to the transmission system and is triggered when the vehicle’s onboard computer detects an issue with the gear ratio monitoring during shifts in 4th gear.
BMW DTC P18D4 symptoms
Symptoms of the BMW DTC P18D4 code may include:
- Harsh shifting or slipping in 4th gear
- Transmission warning light illuminated on the dashboard
- Reduced fuel efficiency
- Decreased overall performance
BMW DTC P18D4 causes
Common causes of the BMW DTC P18D4 code include:
- Low transmission fluid level
- Dirty or contaminated transmission fluid
- Malfunctioning shift solenoids
- Worn or damaged transmission components
BMW DTC P18D4 seriousness
The BMW DTC P18D4 code should be addressed promptly to prevent further damage to the transmission system. Ignoring this fault can lead to more severe transmission issues and potentially result in costly repairs.
How to diagnose DTC P18D4 on BMW
To diagnose the DTC P18D4 code on a BMW, a mechanic may perform the following steps:
- Use a diagnostic scanner to retrieve the fault code and related data
- Inspect the transmission fluid level and condition
- Check for any visible leaks or damage to the transmission components
- Test the shift solenoids and other transmission sensors
How to fix DTC P18D4 on BMW
To fix the DTC P18D4 code on a BMW, the following steps may be taken:
- Top up or replace the transmission fluid if it is low or contaminated
- Clean or replace the shift solenoids if they are faulty
- Repair or replace any damaged transmission components
- Clear the fault code and perform a test drive to ensure the issue is resolved
How to erase DTC P18D4 on BMW
To erase the DTC P18D4 code on a BMW, a diagnostic scanner can be used to clear the fault code from the vehicle’s computer system. Once the repair has been completed and the underlying issue resolved, the code can be cleared to reset the transmission system and turn off the warning light.
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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