P1399 Diagnostic Trouble Code

P1399 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 P1399 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.
Engine surge

Possible Causes :

Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
An air leak forward of the DPF will change the sensor readings resulting in the code
Defective ECU strategies or components will prevent proper regeneration

Repair Processes :

Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code P1399 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 P1399.

Fortunately, P1399 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1399 Trouble Code For Specific Cars

P1399 Mazda B3000 Transmission Transfer Case Differential Lock-Up Feedback Switch Circuit Failure
P1399 Humber 9 Right Rear Center Sensor Circuit Fault
P1399 Tvr V8 Power Steering Pressure Sensor Circuit Range/Performance
P1399 Austin 7 Autolamp Delay Circuit Short To Battery
P1399 Humber Super Right Rear Turn Lamp Circuit Failure
P1399 Triumph Mayflower PATS Received Incorrect Key-Code From Ignition Key Transponder
P1399 Audi Rs4 ASM Mode Circuit High