Case Study
Land Rover Discovery Split Intake Manifold
Our customer booked their Land Rover Discovery 3.0 diesel in for diagnostics after a 'Restricted Performance' warning kept appearing on the dashboard, particularly under load or when driving uphill. A previous garage had replaced the MAF (mass air flow) sensor, but the problem returned, and our customer had spotted oil where they didn't think it should be. The offside intake manifold had split and been replaced around three years earlier, and they had been told the nearside one was fine, so they asked our Land Rover specialist technicians to find the real cause.
Fault Codes
P006A – MAP and MAF correlation
P1247 – Turbo pressure too low
Common Symptoms
- 'Restricted Performance' warning appearing intermittently
- Loss of power under load or when driving uphill
- Oil visible around the top of the engine
- Fault returning after a new MAF sensor was fitted
Land Rover Discovery Diagnostics
We were able to reproduce the fault under higher loads with sustained acceleration. A fault code scan returned P006A and P1247. Fault codes alone aren't enough for an accurate diagnosis, so we read the serial data, which showed the temperature and pressure values were correct with the ignition on and the turbo control data was within specification. The technical bulletins confirmed that intake manifold failure is a common issue on the Land Rover Discovery, something we see all too often. A smoke test of the intake system then revealed a leak on bank 2, the nearside intake manifold. This leak was causing the MAF readings to fall out of specification compared with the MAP readings, triggering the warning.
Vehicles Affected
Land Rover Discovery 4
- Land Rover Discovery 4 2009
- Land Rover Discovery 4 2010
- Land Rover Discovery 4 2011
- Land Rover Discovery 4 2012
- Land Rover Discovery 4 2013
- Land Rover Discovery 4 2014
- Land Rover Discovery 4 2015
- Land Rover Discovery 4 2016
Land Rover Discovery 3
- Land Rover Discovery 3 2004
- Land Rover Discovery 3 2005
- Land Rover Discovery 3 2006
- Land Rover Discovery 3 2007
- Land Rover Discovery 3 2008
- Land Rover Discovery 3 2009
Range Rover Sport
- Range Rover Sport 2005
- Range Rover Sport 2006
- Range Rover Sport 2007
- Range Rover Sport 2008
- Range Rover Sport 2009
- Range Rover Sport 2010
- Range Rover Sport 2011
- Range Rover Sport 2012
- Range Rover Sport 2013
Nearside Intake Manifold Replacement
We replaced the leaking nearside intake manifold. With the engine already stripped, our customer chose to have the front and rear timing belts and tensioners replaced at the same time, as they were due based on their interval and combining the jobs saved on labour. We also replaced both rear upper suspension arms and cleaned up the bolts, then carried out a full wheel alignment once the suspension was reassembled.
Resolution
With the new intake manifold, timing belts and suspension arms fitted and the geometry set up, we took the Discovery out on a test drive. It drove well under load with no warnings or faults, and we returned it to our customer with the 'Restricted Performance' problem fixed.
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