The complete guide to the third generation Range Rover · 2002 to 2012

Range Rover L322 fault codes (DTCs)

A plain-English reference to the trouble codes L322 owners meet most often — what they mean, which system they belong to, and how to approach them. This is a guide to understanding codes, not a substitute for proper diagnosis on the actual car.

The single most important rule: on the L322, a low or tired battery can throw a whole screen of unrelated fault codes across suspension, ABS, transmission and more. Always check battery and charging health first before chasing individual codes — it saves enormous amounts of money and guesswork.

How L322 fault codes work

The L322 is a heavily networked car: its modules (engine, transmission, air suspension, transfer box, body, ABS and more) talk to each other over a CAN bus network. Each module can store its own Diagnostic Trouble Codes (DTCs) when it sees a problem. You'll meet codes in a few different formats:

Generic OBD-II "P" codes (e.g. P0171) — mostly engine and emissions, readable by any code reader.
"U" codes (e.g. U0401) — network/communication faults between modules; very common on the L322 and often a symptom of something else.
"C" codes (e.g. C1A13) — chassis systems such as air suspension and brakes.
Land Rover legacy two-digit codes (e.g. air suspension 22, 32, 64) — shown by some tools and in the air suspension module specifically.

GOOD TO KNOW The same physical fault can show up as several different codes at once. A leaking air spring, for example, can log a pressure code, a height code and a "suspension inactive" state all together. Read the whole picture, not one code in isolation.

Reading and clearing the codes

The diagnostic socket is in the driver's lower fascia / stowage tray. A basic OBD-II reader will pull generic engine "P" codes, but to see and clear the L322's chassis and body codes (suspension, transfer box, body) you need a tool that speaks Land Rover — a GAP IID, Nanocom or dealer-level SDD. Clearing a code without fixing the cause simply means it comes back, so the sequence is always: read → diagnose → fix → then clear to confirm it stays gone.

Air suspension fault codes

By far the most-searched L322 codes. These come from the air suspension (EAS) module. Symptoms are usually a "SUSPENSION INACTIVE" message, the car sitting at one height, refusing to raise, or raising very slowly. See the air suspension page for how the system works.

Code	Typical meaning
22	Reservoir pressure sensor fault (or its wiring)
23	Reservoir pressure supply sensor fault
32	CAN bus communication fault at the suspension module
64	Articulation / cross-axle validity fault (calibration)
C1A00	Compressor not performing to specification
C1A13	Pressure does not decrease when venting the gallery
C1A18	Pressure increases too rapidly when filling the reservoir
C1A20 / CA120-64	Ride-height / "vehicle lifting slowly" related fault
U0421	Invalid data received from ride-level control module

COMPRESSOR NOTE JLR changed the compressor supplier (Hitachi to AMK) during production. If a replacement compressor is a different brand to the original, the software configuration may need updating via a proper diagnostic tool — otherwise the new unit can run on the wrong duty cycle and overheat. Worth knowing before buying a cheap "universal" pump.

CAN bus & communication ("U") codes

"U" codes mean one module isn't getting valid data from another over the network. On the L322 these very often appear in groups — and very often the root cause is not the modules themselves but low battery voltage or a poor earth/connection upsetting the whole bus. Treat a screen full of "U" codes as a prompt to check power and earths first.

Code	Typical meaning
U0401	Invalid data received from engine / powertrain control module
U0402	Invalid data received from transmission control module
U0403	Invalid data received from transfer case control module
U0416	Invalid data received from vehicle dynamics control module
U0421	Invalid data received from ride-level (suspension) module
U0122	Lost communication with vehicle dynamics control module

PATTERN TO RECOGNISE Several "U" codes appearing together, all "invalid data received", with multiple warning lights on the dash, is the classic signature of a power/voltage problem rather than a half-dozen failed modules.

Engine & emissions ("P") codes

These are the generic OBD-II codes any reader can pull. A few are especially common on the L322's engines.

Code	Typical meaning & common L322 cause
P0171	System too lean (bank 1) — often a vacuum / breather (CCV/PCV) hose leak before the MAF sensor
P0174	System too lean (bank 2) — same family of causes as P0171; check induction hoses
P1174	Fuel trim at its limit (bank 1) — commonly traced to perished PCV / breather hoses
P1175	Fuel trim at its limit (bank 2) — same as P1174
P0108	Manifold pressure (MAP) sensor circuit high

DIESEL TIP The lean-running "P017x" codes apply to the petrol V8s. On the 3.6 TDV8, loss of power and limp mode are more often a split intercooler hose or a faulty EGR valve — see common problems.

Transmission & transfer box codes

The L322 used several ZF and GM automatics across its life. Transmission and transfer-box codes often show up as "U" communication faults (above) when voltage is low, but genuine mechanical or solenoid faults will log gearbox-specific codes. Because the gearbox is one of the expensive items, any persistent transmission code — harsh shifts, limp mode, or a fault light — deserves proper diagnosis rather than guesswork. Keeping the gearbox fluid serviced (despite the "sealed for life" label) prevents many of them.

The low-voltage trap (read this)

It's worth repeating because it catches so many owners and even some garages. The L322's modules are sensitive to supply voltage. When the battery is weak, on its way out, or has a poor connection, the network destabilises and modules start logging "invalid data" and dropping offline — producing a cascade of codes and warning lights that have nothing to do with the parts they name.

Before spending a penny on suspension sensors, modules or actuators because of a scary code list, confirm:

The battery is healthy and holding charge (and is the correct type/size).
The battery terminals and earth straps are clean and tight.
There's no parasitic drain flattening it between drives.
There's no water ingress near modules (blocked drains are a classic L322 cause).

Fix the power supply first and a remarkable number of "faults" simply disappear.

What you need to read them

A cheap generic reader is fine for basic engine "P" codes, but to read and clear the L322's chassis, suspension, transfer-box and body codes — and to actually calibrate things afterwards — you want a Land-Rover-literate tool. The enthusiast favourites are the GAP IID and Nanocom; the dealer system is SDD. Given how often a code points to a cheap fix hidden behind a warning light, a proper tool is one of the best investments an L322 owner can make. See diagnostic tools.

In short: read the whole code picture, recognise that grouped "U" codes usually mean a power problem, check battery and earths before buying parts, and use a tool that speaks Land Rover. Most L322 "fault storms" are far cheaper to fix than they first look.

REFERENCE

Code meanings are compiled from owner forums, workshop sources and diagnostic references and are provided as a general guide. Exact definitions and causes can vary by model year, market and module software — always confirm against a proper diagnosis on the specific vehicle.

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