P0393 Diagnostic Trouble Code

P0393 is a kind of OBD-II Diagnostic P-Powertrain 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 P0393 diagnostic trouble code may include:

The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Faulty PCM
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Rich or lean exhaust

Possible Causes :

Faulty IMRC actuator relay (if equipped)
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code P0393 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 P0393.

Fortunately, P0393 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0393 Trouble Code For Specific Cars

P0393 Smart Fortwo Ii Lamp Anti-Theft Indicator Circuit Failure
P0393 Auto-union 1000 Aux Heater Fuel Pump Circuit Open
P0393 Bentley Continental Battery Power Supply ECU Circuit Short To Battery
P0393 Volkswagen Hac Right Front Center Sensor Circuit Failure
P0393 Peugeot 807 Electrodrive Fan 1 Operational Failure (Driver Side)
P0393 Warszawa Warszawa SCP (J1850) Invalid or Missing Data for Interior Environment
P0393 Heuliez Pregunta Passenger's Seat Occupied Switch Circuit Short to Ground