Technical Description of OBD-II Trouble Code
The fuel circuit for Cylinder #2 is experiencing low voltage.
What does that mean?
The OBD trouble code P0264 is a common powertrain code that applies to all vehicles. While the code reference is the same, the repair procedure may vary slightly depending on the manufacturer.
This code indicates that the powertrain control module (PCM) has detected a low voltage situation in the fuel injector for Cylinder #2 in the firing order.
In other words, there is a malfunction in the fuel injector for various possible reasons. It is important to diagnose and fix this problem as soon as possible.
When a fuel injector malfunctions, it causes a ripple effect, leading to changes in the engine’s operating parameters due to mixed signals at the PCM.
If the fuel injector spray pattern is reduced, it results in a lean mixture. This sets off a chain reaction. The oxygen sensor detects the lean mixture and signals it to the PCM. In response, the PCM enriches the fuel mixture for all cylinders, resulting in decreased fuel economy.
The faulty injector in the cylinder causes a lean mixture, which leads to higher cylinder head temperature and detonation. The knock sensor detects the detonation and signals the PCM to retard the timing. As a result, the engine runs rough and lacks power.
This is not the end of the ripple effect, but it gives a general idea of what happens.
Here is a cross-section diagram of a typical automotive fuel injector:
Symptoms
The symptoms associated with code P0264 may include:
Causes
Possible causes for this DTC include:
Diagnosis / Repair
In most cases, this type of problem is caused by a loose or corroded electrical connector on the injector, a fouled injector (dirty or plugged), or a defective injector that needs to be replaced.
Based on my experience of over 45 years, loose or corroded connectors have been the most common cause of electrical faults. There have been only a few cases where low voltage wiring became shorted or open without any disturbance.
The majority of electrical problems were related to the alternator, starter solenoid wiring, oxygen sensor wiring due to its proximity to the exhaust, and battery-related issues. Most electrical work involved correcting customer-installed items such as high-power stereos and other incorrectly installed parts or equipment.
The fuel injectors receive power from the fuel pump relay. The PCM activates the relay when the key is turned on, which means the injectors have power as long as the key is on.
The PCM activates the injector by providing the necessary ground at the right time and for the correct duration.
