P1809 Diagnostic Trouble Code

P1809 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 P1809 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 :

An air leak forward of the DPF will change the sensor readings resulting in the code
Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
Fuel with a large percentage of sulfur will clog the DPF quickly

Repair Processes :

If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs. 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 P1809 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 P1809.

Fortunately, P1809 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1809 Trouble Code For Specific Cars

P1809 Locomobile 40 Timing Reference High Resolution Signal A Malfunction
P1809 Nissan Altima Climate Control A/C Pressure Switch Circuit Short To Ground
P1809 Red Flag Hongki Fuel Volume Regulator Control Circuit Range/Performance
P1809 Seat 133 Injector Circuit Malfunction - Cylinder 2
P1809 Nissan Lucino Column Tilt Feedback Potentiometer Circuit Short to Battery
P1809 Volvo 140 SCP (J1850) Invalid or Missing Data for Chassis Status Request
P1809 Marcos Ts Transmission 4-Wheel Drive High Indicator Short Circuit To Ground