P0203

Injector Circuit Malfunction - Cylinder 3

Car Fault Codes Fuel & air

Can you still drive? With care, short trips only

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 3 hours

Typical cost SAR 100 to 1,500

What it means

This code means the engine computer has found an electrical fault in the fuel injector circuit for cylinder 3, so it can no longer operate the injector properly. The usual result is too little fuel in cylinder 3, a misfire and a shaking engine.

Symptoms4

Check engine light on, possibly with code P0303.
Noticeable engine shaking at idle.
Loss of power, especially on hills or under acceleration.
Fuel smell or higher fuel consumption.

Possible causes5

Loose or corroded cylinder 3 injector connector.
Open or shorted wire in the cylinder 3 injector harness, often from heat or chafing.
Damaged coil in the cylinder 3 injector.
Loss of injector power from a fuse or relay.
Faulty cylinder 3 injector driver inside the engine computer (rare).

How to diagnose6

Visually inspect the cylinder 3 injector connector and wiring and confirm the connector is secure.
Measure the cylinder 3 injector resistance and compare it with the manufacturer specification.
Check supply voltage at the cylinder 3 injector connector and continuity of the wire between the connector and the computer.
Check for drive pulses at injector 3 with a noid light or an oscilloscope.
On port-injection engines, swap the cylinder 3 injector with the one in cylinder 4; if P0204 appears instead, the injector is faulty.
Do not probe direct-injection or diesel injector circuits with an ordinary test light, because they use high voltage.

How to fix6

Reseat, clean or replace the cylinder 3 injector connector.
Repair the damaged wire in the cylinder 3 injector harness and protect it from heat and chafing.
Replace the fuse or relay if injector power is missing.
Replace the cylinder 3 injector if its coil is damaged.
Test or replace the engine computer after ruling out the harness and injector.
Clear the codes, then road test and confirm the code does not return.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

A connector or wire repair is inexpensive; the cost rises when the injector is replaced, with prices depending on the injection type, while a computer repair is rare and much more expensive.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Should I buy a new injector for cylinder 3 right away?

No. Check the connector and wiring and measure the injector resistance first, because many cases of this code come from a corroded connector or damaged wire.

Why does the engine shake with this code?

Because cylinder 3 does not get the fuel it needs and stops contributing power, which unbalances the engine and makes it shake.

Can I drive with this code?

Only a short distance and gently until it is repaired, because an ongoing misfire harms the catalytic converter.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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