How is P0264 different from P0202?

P0202 is an open circuit - a broken connection - on cylinder 2. P0264 is the opposite: the circuit is being pulled low or shorted to earth. The wiring checks differ, so it helps to know which one you have.

Can P0264 damage my ECU?

It can. A sustained short to earth stresses the injector driver inside the ECU. Fixing the short promptly is the best way to avoid an expensive control-module fault.

Will a blown fuse cause P0264?

A blown fuse usually gives an open-circuit code, but the short that blew the fuse is what sets P0264. Replace the fuse only after the short is found and fixed, or it will simply blow again.

Could water cause this code?

Yes. Water in the connector creates a low-resistance path to earth that mimics a wiring short. Drying and resealing the connector often clears the fault.

Do I need a scan tool to fix P0264?

A basic reader shows the code, but live data and a multimeter make diagnosis far quicker by letting you see the circuit state and test for shorts directly.

Is it safe to drive with P0264?

Best not to. Beyond the misfire, an unresolved short can damage the ECU and, if the injector sticks open, wash the bore with fuel. Get it checked before any long trip.

P0264 - Cylinder 2 Injector Circuit Low

What Is P0264?

P0264 is set when the ECU detects a low-voltage or short-to-earth condition on the cylinder 2 injector control circuit. Rather than an open break, the circuit is being pulled to earth somewhere, so the ECU sees the voltage collapse and flags the fault to protect its driver.

A shorted circuit can stop the injector firing cleanly or, worse, leave it switched on. Either way cylinder 2 runs poorly and the ECU may shut the injector down to save its internal driver. Because a dead short can damage the ECU, P0264 should be investigated before driving further.

Common Symptoms

Misfire on cylinder 2
Engine management light, sometimes flashing
Rough idle and hesitation
Fuel smell if the injector sticks open
Blown injector fuse in some cases
Noticeable power loss

Common Causes

Short to earth - the injector control wire chafed against the block or a bracket, the classic cause of a low-circuit code.

Internal injector short - the solenoid winding shorted internally, dragging the circuit low.

Damaged connector - moisture or corrosion bridging the connector pins to earth.

Pinched harness - the loom trapped under a cover or against the head, breaking through the insulation.

ECU driver fault - a shorted driver stage inside the ECU, less common.

Wrong-spec injector - an incorrect injector with the wrong resistance fitted at a previous repair.

How to Diagnose P0264

Read Live Data

Scan the injector circuit status and watch the cylinder 2 reading. A low-side short usually shows the ECU reporting a circuit-low or driver-fault state as soon as the key is on.

Inspect for Chafing

Follow the cylinder 2 injector wire and look for rubbed-through insulation against the engine, brackets, or the cylinder head. A short to earth is the most common reason for P0264.

Check Resistance to Earth

Unplug the injector and measure from each control pin to a good earth. A healthy circuit reads very high resistance; a low reading confirms a short to earth in the wiring or connector.

Test the Injector Itself

Measure across the injector terminals. An abnormally low resistance compared with the others suggests the solenoid has shorted internally and is dragging the circuit down.

Examine the Connector

Look for water tracking, corrosion, or a bent pin touching the body. Dry and clean the connector, then recheck - damp connectors often cause intermittent low-circuit faults.

Isolate Wiring or ECU

With the injector unplugged, if the circuit still reads low to earth the fault is in the harness. If it clears, the injector was the cause. Suspect the ECU only once wiring and injector are proven good.

Mind the ECU DriverA hard short to earth can overload the ECU's injector driver. Do not keep cranking or driving with P0264 active, as repeated shorting risks turning a cheap wiring fault into an expensive ECU repair.

Verdict

Treat P0264 as a short, not a break. Check the cylinder 2 injector wiring for chafing and test for a short to earth first, then measure the injector for an internal short. Suspect the ECU only after the wiring and injector are confirmed good.

Want the full picture? The OBD Fault Code Plain English Guide (PDF) covers the most common UK fault codes in one plain-English download.