This car came to us in restricted performance mode. This is a common fault and every Land Rover Discovery 4 TDV6 or SDV6 will at one point suffer from the restriced performance issue. Typically, this is caused by a cracked intake manifold.

To begin the diagnostic process, we reproduced the fault under higher loads at sustained acceleration. We then scanned the Land Rover for fault codes and found the following:

• P006A – MAP and MAF correlation

• P1247 – Turbo pressure too low

Fault codes alone aren't sufficient to correctly diagnose the issue. Once we have the fault codes, we can carry out a manual inspection and diagnostic process. We continued our diagnostics by reading the serial data. This showed that the temperature and pressure values were correct with the ignition on. The turbo control data was also within specification.

All signs pointed to cracked manifolds. To confirm our suspicions, we performed an intake system smoke test. This revealed a leak on both manifolds.

We stripped the vehicle and replaced both manifolds—a job that took over 12 hours of labour. It is not an easy fix. While we were in there and the car was stripped, we also replaced the front and rear timing belts.