kiran197

My car is messin up an the check engine light came on so i got a buddy of mine wit a scan tool to pull codes an he did po401 an po300b but we don't know what they mean can someone help me........... AND i also took my car to the mitsubishi dealership for the cat recall an the tech pulled codes from my car an it said o2 sensor an mass airflow sensor but here is the catch he could not perform work due to previous modification on vehicle........... so can someone help me is thier a list of codes a can print out an use wit a scan tool

kiran197

ok can someone help

04lancerEsGuy

iTrader: (3)

P0401:

P0401 OBD Trouble Code

Technical Description

Insufficient EGR Flow

What does that mean?

EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor (DPF). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.

Symptoms

You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.

Causes

A code P0401 most likely means one or more of the following has happened:

• The DPF (differential pressure) sensor is faulty and needs to be replaced
• There is a blockage in the EGR (most likely carbon buildup)
• The EGR valve is faulty
• The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions

In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

• Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's. There should be a noticable difference in RPM's with the EGR open
• Clean out the EGR valve to remove deposits
• Replace the DPF sensor
• Replace the EGR valve

04lancerEsGuy

iTrader: (3)

P0300 Code - Cylinder Misfire

Technical Description

Random/Multiple Cylinder Misfire Detected

What does that mean?

Basically this means that the the car's computer has detected that not all of the engine's cylinders are firing properly.

A P0300 OBD code indicates a random or multiple misfire. If the last digit is a number other than zero, it corresponds to the cylinder number that is misfiring. A P0302 code, for example, would tell you cylinder number two is misfiring. Unfortunately, a P0300 doesn't tell you specifically which cylinder(s) is/are mis-firing, nor why.

Symptoms

Symptoms may include:

• the engine may be harder to start
• the engine may stumble / stumble, and/or hesitate
• other symptoms may also be present

Causes

A code P0300 may mean that one or more of the following has happened:

• Faulty spark plugs or wires
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector(s)
• Burned exhaust valve
• Faulty catalytic converter(s)
• Stuck/blocked EGR valve / passages
• Faulty camshaft position sensor
• Defective computer

Possible Solutions

If there are no symptoms, the simplest thing to do is to reset the code and see if it comes back.

If there are symptoms such as the engine is stumbling or hesitating, check all wiring and connectors that lead to the cylinders (i.e. spark plugs). Depending on how long the ignition components have been in the car, it may be a good idea to replace them as part of your regular maintenance schedule. I would suggest spark plugs, spark plug wires, distributor cap, and rotor (if applicable). Otherwise, check the coils (a.k.a. coil packs). In some cases, the catalytic converter has gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.

blaze_125

iTrader: (8)

to lanceresguy

Both codes bring back the EGR valve as a possible source... so that could be your problem.

Now read this:
https://www.evolutionm.net/forums/showthread.php?t=75226