OBD-II Code P0262 — What It Means & How to Fix It

What Does This Error Mean?

P0262 means the electrical signal to the Cylinder 1 fuel injector is reading too high. The engine computer detected more voltage than expected in the injector control circuit. This usually points to a short to power in the wiring or a shorted injector coil. The injector may be stuck open, flooding cylinder 1 with too much fuel. Overfueling one cylinder causes rough running, rich exhaust, and can foul the catalytic converter.

Affected Models

All vehicles 1996+
Common in Ford, GM, Chrysler vehicles
Common in direct injection gasoline engines
Common after wiring harness damage or repairs
Seen in vehicles with heat-damaged injector wiring near exhaust

Common Causes

Short to power in the cylinder 1 injector wiring circuit
Internally shorted injector coil stuck sending high voltage
Damaged wiring harness with a wire shorted against a 12V power source
Shorted injector connector pins bridging the control circuit to battery voltage
ECM driver circuit failure outputting too high a signal on cylinder 1

How to Fix It

Scan for all codes. P0262 paired with a P0301 (cylinder 1 misfire) confirms the bad injector circuit is causing an actual combustion problem. Multiple circuit codes in different cylinders may indicate a wiring harness problem.

If you see injector high codes on multiple cylinders simultaneously, suspect the harness rather than individual injectors.
Inspect the cylinder 1 injector wiring harness. Look for any section that's rubbing against metal or sits near a battery cable or power distribution box. A wire touching a 12V source creates a high-circuit fault.

Pay special attention to any area where a previous repair was done — wiring splices done poorly can cause shorts.
Measure the voltage at the cylinder 1 injector connector with the key on, engine off. If you're seeing battery voltage (12V) on the control wire that should only have a switched signal, there's your short to power.

Compare your reading against the spec in your service manual — the control signal varies by system.
Measure the resistance of the cylinder 1 injector. A shorted injector coil reads very low resistance (close to 0 ohms) instead of the normal 12–17 ohms. Replace the injector if it reads near zero.

A shorted injector can also damage the ECM driver circuit — repair the injector first, then re-check the system.
After fixing the wiring or injector, clear the codes and monitor live data while running the engine. Confirm the injector pulse width for cylinder 1 is behaving normally compared to the other cylinders.

Live injector data on a scan tool shows you the exact on-time for each injector — they should all be similar at idle.

When to Call a Professional

A high-circuit injector code with a confirmed wiring short requires careful electrical diagnosis. If the short is inside the ECM driver circuit, the repair requires specialized ECM testing tools. Don't replace the ECM without a confirmed diagnosis — it's expensive and may not fix the problem. A shop with a good automotive electrician can trace the short in 1–2 hours.

Frequently Asked Questions

Can a shorted injector damage my ECM?

Yes, this is a real risk. The ECM has driver circuits that control each injector. A shorted injector (near-zero ohms resistance) draws much more current than normal. This excess current can burn out the ECM driver circuit. Always fix a shorted injector promptly — and after replacing it, check if the ECM driver output is still functioning correctly.

Will P0262 cause black smoke from the exhaust?

Yes, if the injector is stuck open or over-fueling cylinder 1. Black smoke from gasoline engines means rich combustion — too much fuel, not enough air. You may also notice the smell of raw fuel from the exhaust. This wastes fuel and can damage the oxygen sensors and catalytic converter.

How much does it cost to fix P0262?

Wiring repair: $100–$350. Injector replacement (single): $150–$400 installed. Connector replacement: $50–$200. ECM driver circuit repair: $300–$1,200. Always fix the injector or wiring before addressing any ECM damage.