P1EFC Diagnostic Trouble Code

P1EFC 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 P1EFC 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
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
Fuel with a large percentage of sulfur will clog the DPF quickly

Repair Processes :

It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem. 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. 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 P1EFC 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 P1EFC.

Fortunately, P1EFC is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1EFC Trouble Code For Specific Cars

P1EFC Alfa Romeo 20 ABS Power Relay Output Short Circuit To Ground
P1EFC Mg Zr Ambient Air Temperature Sensor Range/Performance
P1EFC Ferrari 342 Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage
P1EFC Opel Agila Damper RF Circuit Short To Battery
P1EFC Fiat Tempra Left Front Sensor Circuit Failure
P1EFC Bmw X2 Cold Start Injector 2 Malfunction
P1EFC Goliath 1100 Passenger Door Ajar Circuit Short To Battery