U0938 Mitsubishi Lancer Evo 9 Diagnostic Trouble Code

U0938 Mitsubishi Lancer Evo 9 code definition:
U0938 is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code for Mitsubishi Lancer Evo 9.

U0938 Mitsubishi Lancer Evo 9 shows up when there's an electrical problem that causes the fuel volume regulator to malfunction and open. It's quite an unusual problem and likely intermittent. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

Symptoms

Symptoms of a U0938 Mitsubishi Lancer Evo 9 diagnostic trouble code may include:

If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Corroded or damaged connector
Reduction in engine performance, especially at low RPM levels
Malfunction Indicator Lamp (MIL) illuminated

Possible Causes :

Fuel with a large percentage of sulfur will clog the DPF quickly
The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
TFP Valve Position Switch-Drive Without Drive Ratio Problem
Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Look at the plug wires to make sure they are not burnt or laying on the exhaust. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code U0938 Mitsubishi Lancer Evo 9 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 U0938 Mitsubishi Lancer Evo 9.

Fortunately, U0938 Mitsubishi Lancer Evo 9 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.