OBD-II Code P0264 — What It Means & How to Fix It

What Does This Error Mean?

P0264 means the electrical signal to the Cylinder 2 fuel injector is reading too low. The engine computer tried to fire Cylinder 2's injector but detected a lower-than-expected voltage. This typically means a broken wire, corroded connector, or failed injector coil on Cylinder 2. You'll likely feel rough idling and engine misfires on that cylinder. Left unfixed, a dead cylinder sends unburned fuel into the exhaust and can ruin a catalytic converter.

Affected Models

All vehicles 1996+
Common in Ford, GM, Toyota, Honda
Common in vehicles with high-mileage injector wiring
Common after engine work where injectors were removed
Seen in vehicles with heat damage to injector harnesses

Common Causes

Open circuit or broken wire in the cylinder 2 injector control circuit
Corroded or loose connector at the cylinder 2 injector
Cylinder 2 injector coil has failed open — no electrical continuity
Poor engine ground causing low-voltage returns throughout the injector circuits
ECM injector driver failure on the cylinder 2 output

How to Fix It

Check for companion codes. P0264 with P0302 (Cylinder 2 misfire) confirms that cylinder 2 is not firing due to this injector circuit fault. Act quickly — the catalytic converter can be damaged within days of repeated misfires.

A flashing check engine light means active misfires are happening — don't drive further until it's fixed.
Inspect the cylinder 2 injector wiring and connector. Look for damaged insulation, especially near the exhaust manifold where heat can melt wires over time. Clean corroded connector pins with electrical contact cleaner.

Any visible wire damage near Cylinder 2 should be repaired before doing anything else.
Test the cylinder 2 injector resistance with a multimeter across its two terminals. Normal is 12–17 ohms. An open (no reading) or significantly high resistance means the injector coil has failed.

Always disconnect the injector from the harness before measuring — don't test it while connected to the ECM.
Check the engine ground straps. A corroded or loose engine ground causes low voltage returns across all injector circuits — and can trigger low-circuit codes. Clean and tighten all ground connections.

Look for the ground strap running from the engine block to the chassis. It should be clean and tight.
If wiring and ground checks pass and the injector is within spec, have the ECM's cylinder 2 driver circuit tested. A shop can measure the ECM output signal directly with an oscilloscope.

An ECM oscilloscope test costs $100–$200 and definitively rules in or out the ECM as the cause.

When to Call a Professional

If a replacement injector and clean wiring don't resolve P0264, the ECM driver for cylinder 2 may be failed. ECM testing requires specific equipment — have a qualified shop evaluate the module. Don't buy a new ECM until a shop has confirmed it's the cause. ECM repairs and reprogramming run $300–$1,500 depending on the vehicle.

Frequently Asked Questions

How do I know if it's the injector or the wiring?

Test the injector resistance first — if it's out of spec, the injector is bad. If the injector tests fine, inspect the wiring and connector. You can also swap the Cylinder 2 injector with another cylinder's injector. If the fault code follows the injector to its new location, the injector is the problem. If the fault stays on Cylinder 2, the wiring is to blame.

Can I clean my injectors to fix P0264?

Only if the fault is caused by a clogged injector affecting the return circuit. P0264 is an electrical fault — it usually means the injector coil or wiring is the problem, not just deposits. Cleaning won't fix a broken wire or a failed injector coil. Use the swap test and resistance test first to confirm what's actually wrong.

How much does it cost to fix P0264?

Connector repair: $50–$150. Wiring repair: $100–$350. Injector replacement (single): $150–$400 installed. Engine ground repair: $50–$150. ECM repair: $300–$1,500 (rare worst case).