OBD2 Codes P0201–P0208: Fuel Injector Circuit Codes Explained
When your OBD2 scanner returns a P0201, P0202, P0203, P0204, P0205, P0206, P0207, or P0208 code, it is telling you that the ECU detected a problem in the electrical circuit controlling a specific fuel injector. Each code corresponds to one cylinder.
| Code | Cylinder |
|---|---|
| P0201 | Cylinder 1 injector circuit malfunction |
| P0202 | Cylinder 2 injector circuit malfunction |
| P0203 | Cylinder 3 injector circuit malfunction |
| P0204 | Cylinder 4 injector circuit malfunction |
| P0205 | Cylinder 5 injector circuit malfunction |
| P0206 | Cylinder 6 injector circuit malfunction |
| P0207 | Cylinder 7 injector circuit malfunction |
| P0208 | Cylinder 8 injector circuit malfunction |
What Does "Injector Circuit Malfunction" Mean?
The ECU controls each injector by sending a precisely timed electrical pulse to open the solenoid. It simultaneously monitors the circuit for expected current draw. If the circuit draws too much current (shorted coil), too little (open coil or broken wire), or the signal is not returned as expected, the ECU sets a P020X code and illuminates the check engine light.
This is specifically an electrical fault, not a mechanical or flow fault. A clogged injector that delivers less fuel does not trigger P020X codes — it triggers misfire codes (P030X) or fuel trim codes (P0171/P0174). If you have P020X, start with the electrical system.
Common Causes of P0201–P0208
- Failed injector solenoid coil — The most common cause. Coil resistance should measure 12–16 Ω; values outside this range indicate a failed coil requiring injector replacement.
- Broken or corroded wiring — Wires to the injector can chafe on engine components, corrode at the connector, or break at the injector plug. Inspect the harness before condemning the injector.
- Corroded or damaged injector connector — The 2-pin connector on the injector is exposed to heat and vibration. Corrosion causes high resistance in the circuit, triggering the fault.
- Faulty ECU injector driver — Rare, but internal ECU driver failure can set a circuit code. Only diagnose this after ruling out the injector and wiring.
How to Diagnose P020X Codes Step by Step
Step 1 — Confirm which cylinder is affected
Note the specific code number. On a 4-cylinder engine, P0205–P0208 indicate a wiring issue since those cylinders don't exist. Cross-reference with any companion misfire codes (P030X) — they should match the same cylinder number.
Step 2 — Test injector resistance with a multimeter
With the ignition off, unplug the injector connector for the affected cylinder. Set your multimeter to Ω (resistance) and probe the two terminals on the injector body. Normal reading is 12–16 Ω for high-impedance injectors (most port-injection applications) and 2–5 Ω for low-impedance GDI injectors. An OL (open loop) reading means the coil is broken. A near-zero reading means the coil is shorted. Either condition requires replacement.
Step 3 — Inspect the wiring and connector
If resistance is normal, inspect the wiring harness from the ECU to the injector. Look for chafed insulation, green corrosion at the connector terminals, or damage near heat sources. Clean corroded terminals with electrical contact cleaner and a small brush. Repair any damaged wiring.
Step 4 — Use a noid light to verify pulse signal
Plug a noid light into the injector connector and crank the engine. The light should flash rapidly, confirming the ECU is sending the signal. No flash with a known-good injector and clean wiring points to an ECU driver fault.
Step 5 — Clear the code and retest
After any repair, clear the fault code and drive through two complete drive cycles. If the code does not return, the repair was successful. If it returns immediately, continue diagnosis.
Will the Car Start and Drive with a P020X Code?
In most cases, yes — the engine will run on the remaining cylinders. However, you will notice a rough idle, reduced power, and poor fuel economy. Driving for extended periods with a misfiring cylinder can overheat the catalytic converter, potentially causing expensive secondary damage. Diagnose and repair promptly.
If your diagnosis points to a failed injector solenoid, Aurus remanufactured and OEM fuel injectors are flow-tested individually and carry a lifetime warranty — the correct replacement at a fraction of dealer pricing.