ROLLS ROYCE WRAITH RR5 COUPE Engine Control Unit+Wrench

For the Rolls-Royce Wraith (RR5), the Engine Control Unit (ECU) is technically a DME (Digital Motor Electronics) system. Because the Wraith uses a high-output 6.6L V12, the management system is identical in architecture to the Ghost and BMW 760Li, but with a specific “Wraith-only” software map to deliver its 624 bhp.

In 2026, sourcing these parts often involves either a “Plug-and-Drive” cloned kit or a Security Start Kit.

1. Core Part Numbers & Identification

The Wraith uses the Bosch MSD87 platform for early models and the DME 8.x series for later versions (Series II).

2. The “Wrench” (Emergency Key & Tools)

In the context of a Wraith ECU kit, the “wrench” typically refers to one of two critical items needed during the replacement process:

• The Emergency Brake Release “Wrench”: (Part No. 24507590395). If the ECU has failed and the car is stuck in “Park,” you cannot move the vehicle. This specialized red plastic tool (often called a wrench or key) is inserted into a slot under the driver’s side floor mat or in the trunk to manually override the electronic parking brake and transmission lock.

• Mechanical Key Blade: If you purchase a used “Start Kit” (DME + CAS + Key), it must include the mechanical “wrench” (the blade inside the fob). Without this, you cannot manually unlock the door if the battery dies during the programming phase.

• Specialized Sockets: To access the DME (located in the “E-Box” near the passenger-side firewall), you need a 10mm deep socket and a T25/T30 Torx bit to remove the waterproof cowl and the vibration-dampening brackets.

3. The “Start Kit” Strategy

Since a new DME is sold “blank” and requires online coding via a Rolls-Royce server (which many independent shops cannot access), the 2026 market favors Start Kits:

1. DME (Engine Computer)

2. CAS4 or FEM (Security Module)

3. Matched Key Fob Installing all three simultaneously bypasses the need for VIN-coding, as the three parts are already “shaking hands” with each other.

4. Technical Warning: Water Ingress

The most common cause for Wraith ECU failure in 2026 is water ingress into the E-Box.

• The Symptom: Random “Drivetrain Malfunction” warnings or a “No Crank” condition.

• The Fix: Before installing a new ECU, ensure the E-Box Fan and the Cowl Drains are clear. If the drains are clogged with leaves, rain will overflow directly into the engine computer’s wiring harness, shorting out the new unit instantly.

5. Performance Tuning (2026)

If you are replacing the ECU to gain power, specialized tuners (like Gintani or Novitec) now offer OBD Unlock services. This allows you to flash the Wraith’s V12 to reach nearly 700 bhp without removing the hardware, provided the ECU’s “bench lock” has been bypassed.