P1843 Diagnostic Trouble Code

P1843 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 P1843 diagnostic trouble code may include:

Poor acceleration
Cherry red hot catalytic converter
Possible spark knock (detonation / pre-ignition)
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)
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. 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 P1843 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 P1843.

Fortunately, P1843 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P1843 Trouble Code For Specific Cars

P1843 Chevrolet Deluxe Driver's / Passenger's Door Ajar Output Circuit Failure
P1843 Mercedes-benz 230 Air Bag Passenger Circuit Open
P1843 Toyota Raum Park Brake Switch # 2 Released Circuit Failure
P1843 Armstrong Siddeley Sapphire Air Suspension Rear Height Sensor High (SE) Signal Circuit Short To Battery
P1843 Pininfarina Rosso Evap Emission Control Sys Vent Control Valve Circuit
P1843 Ferrari F430 Internal Control Module RAM Error
P1843 Toyota Avalon NVM TIC Failure