P12A9 Diagnostic Trouble Code

P12A9 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 P12A9 diagnostic trouble code may include:

Hesitation upon acceleration
Excessive exhaust leak
Rich or lean exhaust
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)
Some aftermarket accessories and performance modifications

Repair Processes :

Pack the connector cavity with dielectric silicone compound (same stuff they use for light bulb sockets and spark plug wires) and reassemble. 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.

Process Tips

Diagnostic trouble code P12A9 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 P12A9.

Fortunately, P12A9 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P12A9 Trouble Code For Specific Cars

P12A9 Isuzu Vehicross SCP (J1850) Invalid or Missing Data for Vehicle Security
P12A9 Siata Spring Intake Air Volume Circuit Malfunction
P12A9 Nissan Versa Cylinder #5 High To Low Side Short
P12A9 Volvo S70 SCP (J1850) Invalid or Missing Data for Experimental #2
P12A9 Abarth Ot A/C Evaporator Air Temperature Circuit Low
P12A9 Bmw Breyton Climate Control On/Off Switch Circuit Failure
P12A9 Gaz 30 O2 Sensor Circuit Malfunction (Bank 2 Sensor 1)