If you own a modern Mini (F55/F56) or a BMW (X1, 2-Series, etc.), you might be familiar with this annoying scenario: You park the car, put it in 'P', and turn off the engine. Suddenly, the dashboard screams:

"Secure vehicle with parking brake when stationary. Consult Service Center."

This warning often comes with a specific manufacturer fault code: 420106 Shift Lock Solenoid: Selector lever wrongly not locked in P.

The dealership might quote you anywhere from $600 to $1,200 to replace the entire gear selector assembly. But here is the secret: You can fix it yourself for less than $20 with a simple spring replacement. In this guide, we’ll show you how to diagnose it with the iCarsoft CR Ultra P and how to perform the repair.

Step 1: Confirming the Fault with Professional Diagnostics

Before you start tearing apart your interior, you need to confirm the issue. Generic OBD2 scanners often only read "P-codes" (Check Engine lights) and miss transmission or body control codes.

Step 2: The DIY Fix (Replacing the Spring)

The root cause is a small, flimsy return spring inside the gear shifter mechanism. Over time, it loses tension or snaps, failing to trigger the microswitch that tells the computer the car is in "Park."

Tools You Need:

• T20 & T25 Torx drivers
• 10mm & 13mm Sockets
• Plastic Trim Removal Tool
• Replacement Spring (Available on Amazon/eBay for ~$10)

The Process:

• Clear the Area: Slide both front seats forward. Remove the rear cup holder trim and the armrest bolts (13mm).
• Remove Center Console: Unclip the iDrive controller and gear shift boot. You don't need to disconnect everything, but you need to lift the console high enough to access the shifter base.
• Access the Shifter: Remove the 10mm bolts holding the gear selector box to the chassis. You don't need to remove the shifter cables entirely; just create enough wiggle room.
• Open the Mechanism: Carefully unclip the side cover of the gear selector box.
• Replace the Spring: You will likely find the old spring is bent or snapped. Replace it with your new, reinforced spring. Hook it onto the white plastic lever and the metal post.

Step 3: Resetting the System

Once the mechanical part is fixed, the warning light might disappear from the dash, but the "History Code" remains stored in the ECU. This can cause issues with future diagnostics or state inspections.

Plug your iCarsoft CR Ultra P back in:

1. Perform a "Smart Scan."
2. Select the Transmission Module.
3. Choose "Clear Fault Memory."
4. Verify the code 420106 is gone permanently.

Why the iCarsoft CR Ultra P is a Must-Have for BMW/Mini Owners

Fixing this shift lock issue is just one example. European cars are complex, and the CR Ultra P is designed to handle them:

• Battery Registration (BMS): Essential when replacing your BMW's battery to prevent alternator damage.
• EPB Service: Retract electronic parking brakes for brake pad changes.
• Coding Capabilities: The CR Ultra P supports online coding and programming for select BMW chassis, allowing you to adapt new modules or unlock hidden features.

FAQ: Shift Lock Solenoid Fault