Guide To P02B6 OBD Error Code Solutions

<<See All OBD Codes

Is your car engine misfiring and having delayed start up? Is there black smoke emitting from the car exhaust? Is there a sudden drop in the fuel economy? All these are the indications to the OBD Code P02B6 being stored and flashed in the Powertrain Control Module (PCM).

OBD-II Code Decreased engine performance is defined as a Cylinder 8 - Fuel Trim at Max Limit

The PCM utilizes the fuel trim system to increase or decrease fuel delivery and the input signals from the oxygen sensors provide the PCM with the data required to adjust fuel trim. The PCM uses variations in fuel injector pulse width modulation to effect air/fuel ratio changes.

Small variations in fuel trim, typically measured in positive or negative percentage, are normal and hardly cause a code P02B6 to be stored. Maximum fuel trim parameters which can also be positive or negative are normally in the twenty-five-percent range. Once this maximum threshold has been exceeded, a code of this type will be stored.

What causes the problem of Cylinder 8-Fuel Trim at Max Limit?

• Fuel pump fault/failure
• Fuel pump relay fault/failure
• PCM faulty
• Faulty fuel pressure sensor
• Electric fuel pressure regulator faulty
• Fuel filter or other parts of the fuel system clogged/restricted
• Damaged wiring such as a short to ground
• Fuel tank low fuel levels

1. Fuel Pump - Damaged fuel pump will affect the fuel delivery system and the internal combustion process. Replace it immediately.
2. Fuel Pressure Sensor - If the sensor is faulty, the PCM will not be able to interpret the fuel pressure correctly and will affect the fuel delivery system and the engine performance.
3. Fuel Injection - The fuel injection system works by pressurising and injecting the fuel, the system forces it into air that has been compressed to high pressure in the combustion chamber. Replace faulty fuel injectors and parts as it affects the combustion process and the performance output.
4. Diagnostic Tools - Use factory grade OBD scan tools to diagnose an OBD code error problem. Buy quality diagnostic tools from us now!
5. Spark Plugs - Check if the spark plugs are in the right condition and replace them if not. Buy new spark plugs from us now!
6. Powertrain Control Module - Although this error is rare, but check for faulty PCM and if it requires reprogramming or not. Find quality components from us.

P02B6 is considered severe since excessive fuel pressure may lead to a variety of drivability issues and cause internal engine and catalytic converter damage.

Common Symptoms

• Delayed cold start and decreased engine performance
• Black smoke emission from the exhaust system
• Affected fuel efficiency
• Engine Misfires codes stored
• Rough idle and reduced throttle response

Always seek professional help to resolve any OBD code issue. Replace or repair the following components on priority, if found faulty as they are usually the major problematic areas:

• Replacement of Fuel pressure regulator
• Replacement of Fuel pump
• Replacement of Fuel filter
• Replacement of faulty fuel injectors or other fuel system related sensors
• Repairing or replacing electrical wiring or connectors
• Replacement of Faulty fuel pump relay
• Removal of defective fuel pump relay
• Installation of new fuel pump relay
• Testing the fuel pressure and codes cleared with a scanner or gauge

At Parts Avatar Canada, get quality replacement parts and performance parts at the best prices for all your car makes and models.

A mechanic may start with a good visual inspection of the fuel system and the associated components like fuel tank, fuel pump, fuel filter, lines and hoses, electrical wiring & connectors, sensors and injectors.

Examine other problematic parts of your vehicle's fuel system that are not listed here that are specific to your particular vehicle.

During an inspection, make note of any damages to the system and repair them before proceeding with the diagnosis.

After performing the visual inspection, perform a fuel pressure test to test the functionality of all fuel system sensors.

If all the parts are checked for perfect operation, then suspect for faults in the Powertrain Control Module (PCM). Although, this error is rare but faulty components should be repaired or replaced and the system should be reprogrammed for eliminating any error.

Common Mistakes When Diagnosing The P02B6 Code

A most frequent or common mistake when diagnosing the P02B6 code can be replacing the fuel pressure regulator or fuel pump without checking if it is bad or not.

A trouble code is simply a sensor giving a reading that the Powertrain Control Module sees as out of specification. Sometimes, mechanics will see a trouble code and take that for what is actually wrong with the car. Just because a particular part is mentioned in a trouble code, it does not mean that the part is faulty.

• Damaged or contaminated spark plug
• Engine sensor failure
• Exhaust leak
• Fuel injector failure
• Fuel pump failure
• Internal engine failure
• Powertrain Control Module (PCM) software needs to be updated
• The fuel does not meet the manufacturer's requirements