U0304 Diagnostic Trouble Code

U0304 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a U0304 diagnostic trouble code may include:

Misfire
Misfire
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Hesitation upon acceleration

Possible Causes :

A plugged converter will cause of host of driveability problems as well as set this code. A severely plugged converter will result in the inability to increase rpm when under load. Look for a code such as P0421 -- catalytic converter efficiency below threshold if the converter indicating a faulty converter.
Dirty air cleaner element Damaged DPF
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for. If the engine displays a miss and there wasn't a code, determine which cylinder is misfiring. If the exhaust manifold is visible, spay or pour a small amount of water on each cylinder exhaust port. Water will evaporate immediately on good cylinders and slowly on the missing cylinder. If this can't be accomplished pull the plugs and check the condition. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code U0304 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before U0304.

Fortunately, U0304 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

U0304 Trouble Code For Specific Cars

U0304 Gmc Safari Park Brake Applied Warning Lamp Circuit Failure
U0304 Sovam 850 Lamp Backup Switch Input Circuit Short To Battery
U0304 Volkswagen Ea RF LAMP LOW BEAM CIRCUIT Short to Battery
U0304 Proton Preve Fuel Stepper Motor Malfunction
U0304 Suzuki Light Mirror Driver Horizontal Feedback Potentiometer Circuit Open
U0304 Hyundai Veloster SCP (J1850) Invalid or Missing Data for Engine Oil Temp
U0304 Honda Acura Mdx Pressure Control Solenoid B Electrical