P0296 OBD-II Trouble Code: Cylinder 12 Contribution/Balance Fault

P0296 code definition

The P0296 code means that the PCM detects that the voltage reading for the fuel injector circuit in cylinder 12 does not align with the manufacturer’s specifications.

What the P0296 code means

Part of the fuel injection system within the cylinders is a crankshaft. The engine control module, or ECM, measures the rate at which the crankshaft accelerates in order to provide a voltage reading to the PCM. The PCM compares this reading to the manufacturer’s specifications, to ensure that the fuel injection system is working properly. If the values for cylinder 12’s operation do not match up, the PCM stores the P0296 code.

What causes the P0296 code?

In many cases, the fuel injector is either dirty, plugged, or faulty. However, the fuel injector harness may be open or shorted as well. Other causes may include:

• Poor electrical connection in the fuel injector circuit
• Damaged, corroded, or loose wiring, connectors, or other electrical components
• Faulty fuel injector driver in the PCM

What are the symptoms of the P0296 code?

The P0296 is often accompanied by decreased engine performance, including a rough idle, a misfiring engine, and choppy acceleration. The Check Engine Light will be on, and the code will be stored in the PCM. There may also be a noticeable decrease in fuel economy.

How does a mechanic diagnose the P0296 code?

Using an OBD-II scanner, the mechanic should begin by verifying the code, and abstracting any other codes from the PCM to ensure that there is not a wider problem. The first diagnostic test should be a visual inspection of all electrical components, including wiring and connectors. If any of these components are damaged, loose, or missing, they should be repaired or replaced.

After performing this routine, the code should be cleared from the PCM, and the system should be retested. If the code is stored in the PCM again, the mechanic has successfully diagnosed an issue within the fuel injection system, and can begin repairs.

Common mistakes when diagnosing the P0296 code

The only known mistake that is commonly made when addressing the P0296 code is replacing the PCM, thinking that the issue lies in a faulty driver, too early in the diagnosis and repair process. It is very rare for the PCM to be at fault, and far more likely that the issue is a simple matter of shorted circuits or faulty fuel injectors.

How serious is the P0296 code?

Because the P0296 code relates directly to the operation of a vehicle cylinder, this repair is considered very serious. If fuel is not being delivered to the cylinder properly, it could lead to misfire and total transmission failure. When the P0296 code is detected, this issue should be addressed right away.

What repairs can fix the P0296 code?

In order to repair the cause of the P0296 code, there are many things that a mechanic may do. These include:

• Flush, repair, or replace a dirty, plugged, or faulty fuel injector.
• Repair or replace an open or shorted fuel injector.
• Repair or replace any damaged, corroded, or loose wiring, connectors, or other electrical components.
• Replace a faulty PCM.

After each repair, it is important to clear the code from the PCM, and retest this system. This process eliminates features or components, and narrows down the issue until the real cause can be found. Additionally, any other codes that are stored in the PCM should be addressed, particularly if they also relate to the fuel injection system. Two or more codes could be part of a larger issue.

Need help with a P0296 code?

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