BMW DTC P099B – Shift Solenoid ‘G’ Control Circuit Low
DTC P099B meaning on BMW
The DTC P099B code on a BMW indicates an issue with the Shift Solenoid ‘G’ Control Circuit being detected as low. This means that the powertrain control module (PCM) has detected a lower than expected voltage signal from the Shift Solenoid ‘G’ control circuit.
BMW DTC P099B symptoms
Symptoms of the DTC P099B code on a BMW may include:
- Harsh shifting
- Transmission slipping
- Transmission not shifting gears properly
- Check Engine Light illuminated
BMW DTC P099B causes
Common causes of the DTC P099B code on a BMW include:
- Faulty Shift Solenoid ‘G’
- Wiring issues in the Shift Solenoid ‘G’ control circuit
- Low transmission fluid level
- Internal transmission problems
BMW DTC P099B seriousness
The DTC P099B code should be addressed promptly as it can lead to transmission issues and potential damage if left unresolved. Ignoring this code may result in further damage to the transmission system.
How to diagnose DTC P099B on BMW
To diagnose the DTC P099B code on a BMW, a mechanic may perform the following steps:
- Use a scan tool to check for the presence of the code
- Inspect the Shift Solenoid ‘G’ and its wiring for any visible damage
- Check the transmission fluid level and condition
- Perform a test drive to observe the shifting behavior
How to fix DTC P099B on BMW
To fix the DTC P099B code on a BMW, the following steps may be taken:
- Replace the faulty Shift Solenoid ‘G’
- Repair any damaged wiring in the Shift Solenoid ‘G’ control circuit
- Ensure the transmission fluid level is correct and top up if necessary
- If internal transmission issues are found, further diagnostics and repairs may be required
How to erase DTC P099B on BMW
After fixing the underlying issue causing the DTC P099B code on a BMW, the code can be erased using a scan tool. This will clear the code from the PCM’s memory and turn off the Check Engine 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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