P1D9D Diagnostic Trouble Code

P1D9D 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 P1D9D 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
Diminished fuel efficiency

Possible Causes :

Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
An air leak forward of the DPF will change the sensor readings resulting in the code

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. 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. If the scan tool has that capability, and the scan tool can operate the IMRC valves, then the problem is either resolved and a simple code clearing is all that's left or a new PCM would be called for.

Process Tips

Diagnostic trouble code P1D9D 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 P1D9D.

Fortunately, P1D9D is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1D9D Trouble Code For Specific Cars

P1D9D Gilbern Invader Oil Level Lamp Circuit Short To Battery
P1D9D Cisitalia 303 Exhaust Valve Control Solenoid Circuit Low (Bank 2)
P1D9D Koenig C Servo Motor Potentiometer Airintake Right Circuit Short To Ground
P1D9D Willys-overland 685 SCP (J1850) Invalid or Missing Data for Powertrain Status Request
P1D9D Triumph Toledo Pedal Correlation PDS1 and PDS2
P1D9D Ats Gt Air Temperature Internal Sensor Circuit Short To Battery
P1D9D Healey Nash-healey Passenger's Front Seat Down Switch Circuit Short to Battery