OBD2 Diagnostic Code
P0264
Cylinder 2 Injector Circuit Low β Diagnosis & Solutions
P0264 is an electrical fault, not a mechanical one β and that changes everything about how you approach it. Before anyone quotes you a new fuel injector, read this. In most cases the problem is a damaged wire or corroded connector that costs very little to fix.
Severity
8 / 10
High. Cylinder 2 is not firing properly β do not ignore this for long.
Safe to Drive?
Not Recommended
Raw fuel can damage the catalytic converter within days. Engine runs rough and misfires are expected.
Typical DIY Fix Cost
Low β Moderate
Most cases resolved by repairing a connector or harness β not replacing the injector itself.
π What This Code Means
Your engine control module (ECM) controls every fuel injector by sending a precise electrical pulse β open the injector for this many milliseconds, deliver this much fuel. It monitors the voltage on each injector circuit while doing this. P0264 means the ECM measured a voltage that was lower than expected on the cylinder 2 injector circuit.
Think of it like a switch that is stuck on. The ECM commanded the injector to close β to stop flowing β but the circuit voltage did not return to its normal level. That tells the computer something is wrong with the electrical path: a short to ground, a broken wire, a corroded connector pin, or in some cases an injector coil that has internally shorted.
π‘ "Circuit Low" means the voltage on the injector control wire dropped below the ECM's expected threshold. This is an electrical diagnosis β not an injector flow or fuel delivery diagnosis. The injector may be perfectly capable of spraying fuel once the circuit problem is repaired.
Because cylinder 2 is not receiving a clean signal, it may not fire at all or fire erratically. The ECM will usually also set P0302 (Cylinder 2 Misfire) alongside this code.
β‘ Common Symptoms
P0264 almost always comes with noticeable drivability symptoms. Unlike some codes that sit silently, a dead or misfiring cylinder is hard to ignore at idle.
Rough, shaky idle
The engine vibrates noticeably at a stop. With one cylinder not contributing, the other cylinders have to carry the load β you feel it in the steering wheel and seat.
Check engine light on
The CEL comes on immediately. If cylinder 2 is misfiring, you may also see the light flashing β a flashing CEL indicates an active misfire serious enough to damage the catalytic converter.
Noticeable power loss
Acceleration feels sluggish and flat, especially from a stop. On a 4-cylinder engine this is very pronounced β you are down 25% of your cylinders.
Poor fuel economy
The ECM may compensate for the misfire by enriching the mixture on other cylinders, burning more fuel than normal to try to maintain smooth operation.
Fuel smell from exhaust
Unburned fuel exits through the exhaust pipe. You may notice a strong raw fuel odor at the tailpipe β a sign that the cylinder is not combusting its injected fuel.
P0302 stored alongside
The misfire code for cylinder 2 almost always accompanies P0264. Seeing both codes together strongly confirms that cylinder 2 is not firing due to the injector circuit fault.
π― Most Likely Causes
P0264 is almost always an electrical problem, not a mechanical one. Work through this list from the top. Most cases are resolved at cause #1 or #2.
1
Damaged wiring in the injector harnessA chafed, pinched, or broken wire on the cylinder 2 injector circuit is the most common cause. Engine heat and vibration gradually wear through the insulation β especially where harnesses pass near exhaust manifolds or sharp metal edges. A wire touching ground causes the exact low-voltage reading P0264 describes.
~ 38% of cases
2
Corroded or damaged injector connectorThe plastic connector that plugs into the injector body is exposed to heat, moisture, and engine oil. Corroded pins or a connector that has partially backed out of its socket creates resistance and voltage drop on the circuit. This is the most overlooked cause β and the easiest to fix once you find it.
~ 30% of cases
3
Shorted fuel injector (internal coil failure)Inside every injector is a coil of wire that creates a magnetic field to open the needle valve. When that coil develops an internal short, resistance drops far below the normal 11β17 ohms. A healthy injector measured with a multimeter reads 11β17 Ξ©; a shorted one reads below 1β2 Ξ©. The ECM detects this as a low-voltage fault.
~ 18% of cases
4
Poor engine ground connectionInjector circuits share a return path through the engine block ground. A corroded or loose ground strap between the engine and chassis raises resistance in the return circuit. The ECM reads a distorted low-voltage signal even when the injector and wiring are healthy. Ground issues are notorious for producing electrical codes that seem unrelated to the obvious fault.
~ 9% of cases
5
Failed ECM injector driver circuitInside the ECM is a dedicated driver transistor for each injector. If the cylinder 2 driver fails in a shorted state, it pulls the circuit low regardless of what the injector or wiring are doing. This is rare but possible β and it is the one cause where replacing parts first will not solve the problem. Always confirm the injector and wiring are good before considering this.
~ 5% of cases
π§ What to Check First
These three checks cost nothing and require only basic tools. Do them in order β the majority of P0264 cases are solved right here without touching the injector itself.
1
Inspect the cylinder 2 injector connector and wiringWith the engine cold, locate the fuel injector on cylinder 2. Unplug the connector and examine it carefully: look for green or white corrosion on the metal pins, bent or pushed-back terminals, or melted plastic from heat exposure. Then trace the wiring harness back toward the firewall β look for any spot where the insulation is chafed, cracked, or resting against a hot or sharp surface. A corroded pin can be cleaned with electrical contact cleaner; damaged wire insulation needs to be spliced and heat-shrunk.
2
Measure the injector resistance with a multimeterSet your multimeter to the ohms (Ξ©) setting. With the injector connector unplugged, touch the probes to the two terminals on the injector body itself. A healthy port fuel injector reads 11β17 ohms. A reading below 1β2 Ξ© means the coil is shorted internally β that injector needs replacement. A reading of OL (open loop / infinite resistance) means the coil is broken open β also a bad injector. Anything in the normal range means the injector coil is fine and the problem is in the wiring or connector.
3
Check the engine ground strapsLocate the braided metal ground strap that runs from the engine block to the chassis β usually near the battery negative terminal or the firewall. Wiggle it firmly. It should feel solid with zero movement at both attachment points. If it moves or looks corroded at the bolt, loosen the bolt, clean the contact surfaces with sandpaper down to bare metal, reinstall, and clear the code. A bad ground costs nothing to fix and solves a surprising number of electrical codes.
OBD2 Quick Reference Cheat Sheet
The 100 most common codes on one compact printable PDF. Severity rating, safe-to-drive status, and the #1 fix for each code β right in your pocket when you need it most.
$4.99
Get Instant PDF β
β οΈ Common Misdiagnosis
P0264 is an electrical code β but shops sometimes treat it like a mechanical fuel delivery problem. These are the three most expensive wrong turns you want to avoid.
β Misdiagnosis #1 β New injector installed before testing the circuit
A brand-new injector will not fix P0264 if the wiring harness is shorted to ground. The ECM still reads a low-voltage signal on the circuit β the injector just happens to be new now. The only correct first step is to test the circuit resistance and inspect the connector. Any shop ordering a replacement injector before doing this has skipped the diagnostic work entirely.
Potential savings: Cost of injector replacement that was not needed
β Misdiagnosis #2 β ECM replacement recommended for an injector circuit fault
The ECM driver transistor fails in maybe 5% of P0264 cases. Before anyone quotes you a control module, the injector resistance should be confirmed in the 11β17 Ξ© range and the wiring should be confirmed intact end-to-end with a wiring diagram. An ECM diagnosis requires methodical circuit testing β not guesswork. A module replaced before those steps were taken may not solve the problem at all.
Potential savings: Substantial β ECM replacement is one of the most expensive jobs on any vehicle
β Misdiagnosis #3 β Full injector set replaced instead of the single faulty unit
Some shops suggest replacing all injectors at once for "consistency" when only one has failed its resistance test. This is rarely justified unless the vehicle has very high mileage and other injectors have already been tested and found marginal. P0264 identifies cylinder 2 specifically β that is the only injector that needs attention unless testing reveals additional problems.
Potential savings: Cost of multiple injectors versus one
π° Estimated Repair Cost
DIY cost = parts only. Shop cost = parts plus labor. Ranges vary by vehicle, region, and shop rate. Use these as a planning guide β not a fixed quote.
Injector connector & pigtail replacement
DIYVery Low
ShopLow
LevelEasy
Wiring harness repair (splice & seal)
DIYVery Low
ShopLowβModerate
LevelModerate
Engine ground strap replacement
DIYVery Low
ShopLow
LevelVery Easy
Single fuel injector replacement
DIYModerate
ShopModerateβHigh
LevelModerate
Full injector harness replacement
DIYModerate
ShopHigh
LevelAdvanced
ECM replacement (last resort only)
DIYHigh
ShopVery High
LevelProfessional
β
In the majority of verified P0264 cases, the fix is a connector repair or wiring splice β not a new injector. Test before you buy anything.
OBD2 Decoded: The 100 Most Common Codes & the Questions Mechanics Fear
Includes the P0264 decision tree, false-positive traps, and the exact questions to ask before authorizing any repair. The 100 most common codes β all covered. Walk into any shop fully prepared.
$14.99
Get the Full e-Book β
π Most Reported On
P0264 can appear on any gasoline-powered vehicle with sequential fuel injection. These models generate the most owner reports and verified repair records for this specific code.
Chevrolet Silverado (2007β2014, 5.3L / 6.0L)
GMC Sierra (2007β2014, 5.3L / 6.0L)
Dodge Ram 1500 (2009β2015, 5.7L Hemi)
Ford F-150 (2011β2016, 5.0L)
BMW 3 Series (2006β2012, N52/N54 engine)
Volkswagen Jetta (2008β2014, 2.0L / 2.5L)
Toyota Camry (2007β2011, 2.4L 2AZ-FE)
Jeep Grand Cherokee (2011β2016, 5.7L)
β Frequently Asked Questions
Can I drive with P0264 active?
Only for very short distances to reach a shop. Cylinder 2 is not firing correctly β you are effectively running a misfiring engine. Raw unburned fuel can damage the catalytic converter within days. A flashing check engine light means damage is happening right now β pull over immediately. Get it diagnosed quickly. This is not a code to park and revisit next week.
Will P0264 always mean the injector is bad?
No β and this is the most important thing to understand about this code. The majority of P0264 cases are caused by damaged wiring or a corroded connector between the ECM and the injector. The injector itself is the wrong starting point. Test the circuit and inspect the connector first. A simple multimeter reading in under five minutes tells you whether the injector coil is actually shorted before you spend anything.
What resistance should a healthy injector measure?
Most port fuel injectors measure between 11 and 17 ohms. High-impedance injectors typical of modern gasoline engines fall in this range. A reading below 1β2 Ξ© indicates a short circuit inside the injector body. A reading of OL (open loop) means the internal coil has broken open. Always verify the specification for your specific vehicle first β some direct injection (GDI) systems use different values β but 11β17 Ξ© covers the vast majority of engines you will encounter.
Can a bad ground cause P0264?
Yes, and it is more common than most people expect. The injector circuit relies on a clean return path back to the ECM through the engine block ground. A corroded or loose ground strap raises resistance in that return path, causing the ECM to read a low-voltage condition on the circuit even when the injector and wiring are perfectly healthy. If the injector tests good and the wiring looks clean, check both ground attachment points β block to chassis and block to battery negative β before going any further.
Does P0264 cause a misfire code at the same time?
Very often yes. If the injector circuit fault prevents cylinder 2 from firing reliably, the ECM will also set P0302 (Cylinder 2 Misfire Detected). Seeing both codes together strongly confirms that cylinder 2 is not receiving a clean injector signal. The injector wiring harness and connector are always the right starting point when these two codes appear together.
π Related Codes
These codes share the same injector circuit family or commonly appear alongside P0264.
This guide is for informational purposes only. Always consult a qualified mechanic before performing any vehicle repair. OBDPlatform is not responsible for actions taken based on this content.