Symptoms
Judder and hesitation at low-speed acceleration, especially on 1–2 and 2–3 shifts, then P0401 (EGR flow insufficient) and sometimes P006B.
The fix, step by step
- Log demanded versus actual EGR valve position with a diagnostic tool.
- In one documented 3.0 diesel case, the dealer replaced the inlet manifold pressure sensor but the fault returned.
- A member pointed to the exhaust pressure sensor in the 90-degree bend just after the turbo, whose narrow pipe can block with soot and confuse the EGR logic.
- If the valve itself is sticking, clean or replace it; short-trip use makes this worse.
Tools & part numbers
- Diagnostic tool with live data, sockets
- exhaust pressure sensor pipe, EGR valve (as diagnosed)
Where to buy the parts
Exhaust gas pressure sensor (search, confirm fitment)LR Direct ↗
Defender 2020 EGR valve and sensors (search)Rovers North ↗
Hunting a used or discontinued part? Search eBay Motors for Land Rover Defender (L663) parts →
Rated for a competent home mechanic with a decent tool kit. Confirm torque figures, fluids and procedures against the factory service manual for your VIN, support the truck on stands rather than a jack, and work at your own risk (disclaimer). Some parts links are affiliate links, which pay us a small commission at no cost to you.