TD4, SD4, TDV6, SDV6 & TDV8 EGR Codes Explained

Land Rover and Range Rover diesels are torque-heavy, emissions-controlled platforms. When EGR flow becomes unstable, the ECU intervenes by limiting torque to protect emissions compliance.

If you are experiencing:

• Limp mode under load

• Hesitation between 1,500–2,500 rpm

• Flat throttle response

• Repeat EGR or airflow fault codes

• Underboost warnings

• DPF or regeneration complaints

Identifying your engine family is the first step.

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Freelander 2 & Evoque 2.2 Diesel

224DT Engine Family

Common Applications

Engine Code

• 224DT (PSA DW12-based platform)

EGR System Behaviour

• Single cooled EGR valve

• DPF integration

• Variable turbo control

• Torque-based ECU strategy

Common faults:

• P0401 insufficient flow

• P0404 range/performance

• MAF plausibility errors

• Limp mode under load

These engines are extremely sensitive to airflow deviation caused by intake contamination.

Discovery 3 & Early Range Rover Sport

2.7 TDV6 – 276DT Engine

Common Applications

Engine Code

• 276DT

EGR Layout

• Dual EGR valves (left & right bank)

• Cooled EGR system

• Variable turbo

Typical symptoms:

• Hesitation during acceleration

• Limp mode when overtaking

• Black smoke under load

• P0401 / P0404

• Underboost codes

If one EGR valve sticks, airflow imbalance triggers torque intervention.

Discovery 4, Range Rover Sport & L322

3.0 TDV6 – 306DT Engine

Common Applications

Engine Code

• 306DT

EGR Characteristics

• Twin turbochargers

• Dual EGR valves

• DPF integration

• Strict torque modelling

When EGR flow becomes unstable:

• Boost deviation may log

• P0401 and airflow faults appear

• Limp mode may trigger intermittently

These engines are particularly sensitive to carbon buildup in intake runners.

Range Rover L322 & Sport

3.6 TDV8 – 368DT Engine

Common Applications

Engine Code

• 368DT

System Overview

• Twin turbo V8 diesel

• Cooled EGR

• DPF filtration

• High torque output

Symptoms when EGR flow deviates:

• Sudden torque drop

• Underboost condition

• Hesitation at mid-range RPM

• P0401 / P0404

On heavy vehicles, airflow deviation is immediately noticeable.

Range Rover L405 & Sport

4.4 SDV8 – 448DT Engine

Common Applications

Engine Code

• 448DT

System Overview

• Updated cooled EGR

• SCR / AdBlue integration

• DPF system

• Advanced torque-based calibration

EGR instability may interact with NOx control and regeneration strategy, causing complex intermittent faults.

Discovery 5 & Range Rover Velar

2.0 Ingenium Diesel – AJ200D Engine

Common Applications

Engine Code

• AJ200D (Ingenium)

EGR Characteristics

• Electronically controlled cooled EGR

• DPF and SCR integration

• Highly emissions-dependent torque strategy

Common complaints:

• Limp mode with no severe noise

• Airflow plausibility errors

• P0401 combined with NOx-related faults

These engines are extremely calibration-sensitive.

Defender 2.2 TDCi

Puma Engine

Applications

Common issues:

• EGR valve sticking

• Hesitation

• Limp mode

• Airflow faults

Simpler hardware, but still torque-limited by ECU strategy.

Land Rover & Range Rover EGR Fault Codes

The fault code is the warning.
The airflow modelling and torque strategy cause the driveability issue.

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Remap & Driveability Optimisation

Where appropriate, a professionally developed ECU calibration can:

• Optimise airflow modelling

• Improve low-end torque

• Reduce hesitation

• Restore smooth acceleration

• Improve fuel efficiency

Calibration must remain safe and within mechanical limits.

We do not physically remove required emissions hardware.
We do not create excessive smoke or visible emissions.

MOT & Road Compliance

UK diesel MOT testing focuses on:

• Visible smoke levels

• Active warning lights

• Presence of required emissions equipment

A properly calibrated Land Rover or Range Rover with functioning emissions hardware and no active warning lights will not fail its MOT purely because it has been professionally remapped.

When To Make An Enquiry

If your:

• Freelander 2 TD4 / SD4

• Discovery 3 / 4

• Discovery 5

• Range Rover Evoque

• Range Rover Velar

• Range Rover Sport

• Range Rover L322 or L405

• Defender 2.2

is showing:

• Limp mode

• Hesitation

• P0401 / P0403 / P0404

• Underboost

• Repeat airflow faults

Send:

• Registration

• Postcode

• Engine code (if known)

• Stored fault codes

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