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OBDII Codes Possible Causes

What OBDII Codes Possible Causes Means:

The "Possible Causes" is the list of all the items, components, or circuits that should be inspected, tested, repaired, or replaced to fix the OBDII code. AutoCodes.com's goal is to help you find the best possible solution to your OBDII code problem.

Faulty or Failed component


It means that the component is more than likely the cause of the code, and that needs to be replaced.

Engine mechanical problems


When "engine mechanical problem" is listed as possible causes of the OBDII code, it means that the problem is not caused by an electronic component, but by a mechanical component such as pistons,
valves, mechanical pump, etc.

Engine Lean System (Lean Mixture)


"Engine Lean" or "Lean Mixture" means there is an excess of air during the engine combustion. The ideal Air/Fuel (A/F) ratio is 14.7:1, which means 14.7 parts of air to one part of fuel.
Intake gaskets, faulty Mass Air Flow (MAF), and faulty A/F Sensors are common problems when the engine is running too lean.

Engine Rich System (Rich Mixture)


"Engine Rich" or "Rich Mixture" means there is an excess of fuel during engine combustion. The ideal Air/Fuel (A/F) ratio is 14.7:1, which means 14.7 parts of air to one part of fuel.
Leaking fuel injectors, bad spark plugs, faulty Mass Air Flow (MAF), and faulty A/F Sensors, are common problems when the engine is running too rich.

Circuit poor electrical connection


It means that the component (sensor, solenoids, actuator, etc.) connector is not fully connected or is disconnected. Before replacing any components, try fully disconnecting the connector, reconnect and test the system or component again.

Harness is open or shorted


It means that the wire(s) connected from and to the component (sensor, solenoids, actuator, etc.) is either open (cut, broken, disconnected) or shorted (touching other wires, components, body). "Open" and "short" are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of the wire to the ground or another wire.
In simple electronics, this usually means something won't work at all. With complex electronics (such as ECMs or PCMs) this can sometimes mean something works, but not the way it's supposed to.

Wire circuit example:

OBDII Codes Possible Causes