What is the difference between P0202 and P0264?

Both point at the cylinder 2 injector circuit but describe different electrical faults. P0202 is an open circuit — the path is broken. P0264 is a low reading, which usually means the circuit is shorted to ground or the injector coil is internally shorted. The tests overlap, but with P0264 you are hunting a short rather than a break.

How do I know which cylinder is number 2?

On an inline engine it is the second cylinder from the front, next to cylinder 1. On a V engine it varies by manufacturer — some number across the banks so cylinder 2 is on the opposite side from cylinder 1, and others number down one bank first. Look up the firing-order and cylinder-numbering diagram for your exact engine before replacing an injector.

Is it the injector or the wiring?

The resistance test tells you quickly. Unplug the cylinder 2 injector and measure the coil against specification and against the other injectors. A reading far below spec condemns the injector. If it measures correctly, check the control wire for continuity to ground with everything disconnected, which finds a chafed harness.

Can I keep driving with P0264?

It is best not to. A misfiring cylinder 2 sends raw air and unburned fuel into the exhaust, which can overheat the catalytic converter — a repair that costs far more than the injector. Drive gently and directly to a shop, and stop driving entirely if the check engine light is flashing.

OBD-II trouble code

P0264: Cylinder 2 Injector Circuit Low

The engine computer saw the cylinder 2 fuel injector control circuit read low — usually a wire shorted to ground or a shorted injector coil. Cylinder 2 typically misfires, so diagnose it before the catalytic converter is damaged.

Medium severityPowertrainFuel InjectorsDo not drive

Quick facts

System: Powertrain
Category: Fuel Injectors
Severity: Medium severity
Drivable: No — stop driving until repaired
Repair cost range: $50 – $1,500
DIY difficulty: Intermediate DIY

What does P0264 mean?

Fuel injectors are switched on the ground side. Battery voltage sits on one terminal of the injector while the engine control module (ECM) pulls the other terminal to ground for a precise number of milliseconds to open it. Between pulses that control wire should read near battery voltage, because it is not connected to anything conductive.

P0264 sets when the ECM sees the cylinder 2 control circuit reading low when it should be sitting high. That normally means the circuit is grounded when it should be floating — a control wire that has chafed through to the engine block or body, an injector with a shorted coil winding, or corrosion and moisture bridging pins inside the connector. Some manufacturers set the same code when measured circuit current is out of range low.

The code names cylinder 2 specifically, so diagnosis is targeted, but you need the correct cylinder-numbering diagram for your engine. On an inline engine, cylinder 2 is the second from the front. On a V engine, cylinder 2 may be the front cylinder of the opposite bank on some manufacturers and the second cylinder of Bank 1 on others — do not guess. Expect a cylinder 2 misfire (often a companion P0302) along with rough running and reduced power, and be aware that a sustained misfire can overheat and destroy the catalytic converter.

Common causes

Cylinder 2 injector control wire chafed and shorted to ground
Shorted coil winding inside the cylinder 2 injector
Corrosion or moisture bridging terminals in the cylinder 2 injector connector
Harness damage from heat near the exhaust manifold
Pinched wire under an intake manifold or valve cover after recent service
Rarely, a failed cylinder 2 injector driver inside the ECM/PCM

Symptoms

Check engine light on, sometimes flashing under load
Rough idle and engine shake
Cylinder 2 misfire, commonly with a companion P0302
Reduced power and hesitation on acceleration
Increased fuel consumption or a raw fuel smell
Hard starting in some cases

Diagnostic steps

1.Confirm P0264 and record companion codes — a cylinder 2 misfire (P0302) or the paired high-circuit code P0265 changes the diagnostic path.
2.Look up the cylinder-numbering diagram for your specific engine and locate cylinder 2 before touching anything.
3.Inspect the cylinder 2 injector connector and pigtail for corrosion, melted insulation, and backed-out pins.
4.Disconnect the injector and measure its coil resistance with the key off. Compare to specification and to the other injectors — a reading well below spec indicates a shorted coil.
5.With the injector and the ECM connector both unplugged, check the control wire for continuity to ground. Any continuity confirms a short in the harness.
6.Wiggle-test the harness from the injector back toward the firewall, focusing on chafe points near the exhaust manifold, manifold studs, and harness clips.
7.Once the wiring checks out, use a noid light or a scan tool injector test to confirm the ECM is pulsing the circuit normally; no correct pulse with good wiring points at the ECM driver.

Repair cost

$50 – $1,500

Repairing a chafed wire or corroded connector is often $75-$250. A single fuel injector runs $60-$400 in parts plus 0.5-3 hours of labor depending on accessibility. A failed ECM injector driver is uncommon and runs $500-$1,500 with programming. Diagnosis alone is typically $75-$150.

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DIY vs shop

This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.