P0203 on Land Rover
Injector Circuit/Open - Cylinder 3
P0203 on Land Rover vehicles indicates injector circuit/open - cylinder 3. Au7o has documented this code across 1 Land Rover model — most commonly on Defender. This code means the Engine Control Module detected an electrical problem (open circuit or out-of-range resistance) in the fuel injector control circuit for cylinder 3. The ECM pulses each injector electrically and watches the circuit to verify it is operating. P0203 means the expected feedback for cylinder 3's injector is missing or abnormal, so that cylinder may not be fueling properly. The typical result is a misfire, rough idle, and reduced performance traceable to cylinder 3. Typical repair costs on Land Rover range from $30 to $250, depending on the specific model and root cause.
Common Causes of P0203
- •Damaged or corroded injector connector at cylinder 3
- •Open or shorted wiring in the injector control circuit
- •Failed (electrically open) fuel injector on cylinder 3
- •Loose or backed-out connector pin
- •Poor ground or power feed to the injector
- •Faulty injector driver inside the ECM/PCM
- •Chafed harness causing intermittent open
P0203 on Land Rover by Model
Land Rover Defender(1 issue)
- Oil wicks up the injector harness into the ECU — misfires, no-start, random codes1999-2006
A hardening rocker-cover/injector seal lets engine oil into the under-cover injector harness. Oil then travels by capillary action ALONG the copper strands inside the loom, past the rocker-cover connector and down the engine loom — sometimes all the way to the ECU's red plug. Once oil corrupts the injector signal path you get bizarre, intermittent faults: misfires, rough idle, hard/no-start, cutting out and random fault codes that chasing sensors won't fix. It is one of the most common and most misdiagnosed Td5 electrical gremlins.
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View P0203 across all makes →Frequently Asked Questions
What does P0203 mean on Land Rover?▼
P0203 stands for "Injector Circuit/Open - Cylinder 3." This code means the Engine Control Module detected an electrical problem (open circuit or out-of-range resistance) in the fuel injector control circuit for cylinder 3. The ECM pulses each injector electrically and watches the circuit to verify it is operating. P0203 means the expected feedback for cylinder 3's injector is missing or abnormal, so that cylinder may not be fueling properly. The typical result is a misfire, rough idle, and reduced performance traceable to cylinder 3. On Land Rover specifically, this code is documented across 1 model.
What causes P0203 on Land Rover vehicles?▼
Common causes on Land Rover: Damaged or corroded injector connector at cylinder 3, Open or shorted wiring in the injector control circuit, Failed (electrically open) fuel injector on cylinder 3, Loose or backed-out connector pin, Poor ground or power feed to the injector. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0203 on a Land Rover?▼
Repair costs on Land Rover range from $30 to $250, depending on the specific model and root cause.
Which Land Rover models have P0203 documented?▼
Au7o has documented P0203 on 1 Land Rover model: Defender.