P120A Diagnostic Trouble Code

P120A 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 P120A diagnostic trouble code may include:

Excessive exhaust leak
Hesitation upon acceleration
Malfunction Indicator Lamp (MIL) illuminated
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

Look for rubbing, scraping, bare wires, worn spots or melted plastic connectors. Pull the connectors apart and carefully look at the terminals (the metal parts) inside the connectors. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. 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.

Process Tips

Diagnostic trouble code P120A 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 P120A.

Fortunately, P120A is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P120A Trouble Code For Specific Cars

P120A Chrysler Firepower Evaporative Emission (EVAP) System Flow During Non-Purge Oldsmobile Only
P120A Citroen Gs Fuel Level Sensor Circuit Range/Performance
P120A Renault Altica Gear Shift Forward Actuator Circuit / Open [forward motion, odd gears, 1,3,5]
P120A Mercury Ln7 Air Suspension LR Height Sensor Circuit Failure
P120A Alfa Romeo Gp159 Air Assist Control Valve Range/Performance
P120A Toyota Raum Park Brake Switch # 2 Released Circuit Failure
P120A Talbot Alpine Mirror Passenger Horizontal Feedback Potentiometer Circuit Short to Ground