P0264
PowertrainCylinder #2 Injector Circuit Low
Usually you'll notice the car shaking a bit at idle, maybe a stumble when you pull away, and that orange engine light glowing on the dash. What the ECU is actually telling you is that the wire feeding the cylinder 2 injector is showing less voltage than it expects when it tries to fire that injector. That can mean the injector itself, the wiring to it, or the connector. The end result is cylinder 2 not getting fuel the way it should, so the engine runs down on one pot.
ⓘ Information only. This page provides general educational information about fault code P0264. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0264 mean?
P0264 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder #2 Injector Circuit Low.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Engine light on, sometimes with the car dropping into limp mode if the misfire gets bad
- • Lumpy, shaky idle that you can feel through the steering wheel and pedals
- • A flat spot or stumble when you accelerate, like the engine briefly catches its breath
- • Down on power, especially noticeable going up a motorway slip road or pulling a load
- • A distinct misfire that's always on the same cylinder rather than wandering about
- • Harder cold starts and the odd whiff of unburnt fuel from the exhaust
Possible causes
Causes commonly associated with P0264, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Dodgy connector or wiring at the cylinder 2 injector. This is the first thing to suspect because the plugs sit in a hot, vibrating engine bay and the pins corrode or back out
- 2. The injector itself has gone open circuit or developed high resistance internally, so the ECU can't drive it properly
- 3. A chafed or broken wire in the injector loom, often where the harness rubs on a bracket or the rocker cover
- 4. Short to earth in the injector control wire, which the ECU reads as a low signal
- 5. Pins pushed back or green with corrosion at the ECU connector, less common but it happens on older cars
- 6. Failed injector driver inside the ECU itself, which is the expensive one and the last thing you confirm
- 7. An injector that's partially blocked and drawing odd current, occasionally enough to trip the circuit code
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Unplug the cylinder 2 injector connector and have a proper look. Spread the pins, check for corrosion, green crust, or a connector that wasn't fully clicked home. A surprising number of these are just a bad connection
- 2. Read the live data and freeze frame. See whether cylinder 2 is the only one misfiring and under what conditions the code logged, cold start versus warm idle tells you a lot
- 3. Measure the injector resistance across its terminals with a multimeter. Most petrol injectors sit around 12 to 16 ohms, diesels much lower. Compare it against a known-good injector on the same engine. Open circuit or way out of range and the injector is your answer
- 4. Back-probe the wiring and check continuity from the ECU connector to the injector, and check for a short to earth. This separates a wiring fault from a duff injector
- 5. Swap the cylinder 2 injector with one from another cylinder if it's a quick job, then clear the code and drive it. If the fault follows the injector, you've found it. If it stays on cylinder 2, the problem is in the wiring or the ECU
- 6. Clear the codes and road test properly, not just a lap of the car park. Get it warm and put it under load to confirm the fault's actually gone
Common questions about P0264
How do I work out whether it's the injector or just the wiring on my car? +
Start at the connector, because a bad plug or corroded pin is cheaper and more common than a dead injector. If the connector's clean and seated, measure the injector resistance and compare it to the other cylinders. An injector reading wildly different from its mates is the culprit. If the resistance is fine, the trouble is in the loom or the ECU, so test continuity along the control wire and look for a short to earth. The quickest confirmation is swapping the cylinder 2 injector with a neighbouring one. If the code jumps to the new cylinder, you've got a faulty injector. If it stubbornly stays on cylinder 2, it's wiring or the driver inside the ECU.
Can I sort this myself or is it a garage job? +
The connector and basic wiring checks are well within reach if you can use a multimeter and aren't afraid of a few electrical readings. Cleaning a corroded plug, reseating pins, or repairing a chafed wire can be a free or near-free fix. Replacing the injector is a bigger ask. On a lot of engines you have to depressurise the fuel rail and remove the inlet manifold to get at it, and the parts run anywhere from around £40 for a basic petrol injector to a few hundred for a diesel unit. If the injector is buried or you're not comfortable working around live fuel, hand it to an independent garage.
If I clear the code will it stay gone or come straight back? +
It comes back if you haven't fixed the cause, usually within a few miles or by the next cold start. P0264 is an electrical circuit fault, so the ECU re-checks that injector every time it fires and trips the code again the moment it sees the low signal. The only time clearing it sticks is when the real problem was a loose or dirty connector that you've since cleaned and reseated, or after you've actually replaced the injector or repaired the wire. Clearing the code on its own is just turning the light off, not a repair.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →