What Does It Mean?
This diagnostic trouble code (DTC) is a generic powertrain code, meaning it applies to vehicles equipped with OBD-II. Although generic, specific repair steps may vary by make/model.
The OBD fault code P0267 is a generic powertrain code common to all vehicles. Although the code reference is the same, the repair procedure may vary somewhat by manufacturer.
This code implies that the Powertrain Control Module (PCM) has experienced a low voltage situation involving the fuel injector for cylinder number 3 in the firing order.
In short, this fuel injector is malfunctioning for one of many reasons. It is important to diagnose and repair this type of issue as soon as possible.
When a fuel injector malfunctions, it causes ripples throughout the system, meaning the engine’s operating parameters change due to mixed signals being sent to the PCM.
If the fuel injector’s spray pattern is reduced, a lean mixture will result. The ripple effect begins. The oxygen sensor signals a lean mixture to the PCM. In response, it enriches the fuel mixture for all cylinders. Fuel economy drops.
The cylinder with the faulty injector causes a lean mixture which in turn causes a higher cylinder head temperature leading to detonation. The knock sensor detects the detonation, signals the PCM which responds by retarding the timing. Now the engine runs roughly and lacks power.
This isn’t the end of the ripple effect, but it reflects the general idea.
Cross-section diagram of a typical automotive fuel injector
Symptoms
Symptoms displayed for a P0267 code may include:
Check Engine Light illuminated and P0267 code set
Engine will run rougher than normal
Lack of power
A significant drop in fuel economy will result
Causes
Possible causes of this DTC include:
Dirty fuel injector supplying cylinder number three
Faulty fuel injector
Clogged fuel injector
Open or short in the fuel injector harness
Loose or corroded fuel injector connector
Diagnosis / Repair
Generally, this type of problem is either a loose or corroded electrical connector on the injector, a clogged (dirty or blocked) injector, or a bad injector requiring replacement.
In over 45 years, I have found that loose or corroded connectors were the cause of the electrical fault most of the time. I have only found a few instances where the low voltage wiring became shorted or open (when it hasn’t been disturbed).
The majority of electrical problems were related to the alternator, starter solenoid wiring, oxygen sensor wiring due to the immediate proximity of the exhaust, and the battery. The majority of electrical work involved correcting items installed by the customer, such as high-power stereo systems and other improperly installed parts or equipment.
Fuel injectors are powered by the fuel pump relay. The PCM activates the relay when the key is turned on. This means that as long as the key is on, the injectors have power.
The PCM activates the injector by providing the ground at the necessary time and for the appropriate duration.
Check the connector on the fuel injector. This is a plastic connector attached to the injector with a metal clip around the connector. Pull on the connector to see if it comes off easily. Remove the wire tie and remove the connector from the injector.
Inspect the harness connector for corrosion or pushed-back pins. Ensure the two blades are not bent on the injector itself. Correct any faults and apply dielectric grease and install the electrical connector.
Start the engine and listen to the injector to ensure it is operating. Use a long screwdriver on the injector and the handle to your ear and you can hear it clearly. If it doesn’t make a very audible “clicking” noise, it either has no power or it has failed.
If it wasn’t clicking, remove the connector from the injector and check for power with a voltmeter. No power means the wiring from the fuel pump relay is faulty or has a loose connection. If it has power, probe both terminals on the harness connector and if the PCM injector driver is working, the voltmeter will show rapid pulses. If pulses are observed, replace the injector.
If the injector was operating, it is either clogged or dirty. Try cleaning it first. The injector flush kit is inexpensive and will benefit the remaining injectors, potentially preventing a recurrence. If flushing doesn’t solve the problem, the injector must be replaced.
Purchase an “in-line” fuel injector flush kit online or at an auto parts store. It will consist of a can of high-pressure injector cleaner and a hose with one end for the injector cleaner can’s threads.
Pull the fuse to the fuel pump.
Start the vehicle and let it run until it dies from lack of fuel.
Remove and plug the fuel return line attached to the fuel pressure regulator. This is to prevent the cleaner from going back into the fuel tank.
Remove the Schrader valve in the test port of the fuel rail. Install the fuel line from the flush kit onto this test port. Screw the can of high-pressure fuel injector cleaner onto the fuel line of the flush kit.
Start the engine and let it run until it runs out of fuel. It will run solely on the can of cleaner.
When the engine stops, turn the key off, remove the line from the flush kit, and replace the Schrader valve. Install the fuel pump fuse.