B1841 Diagnostic Trouble Code

B1841 is a kind of OBD-II Diagnostic B-Body 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 B1841 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 :

Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. 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. Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications.

Process Tips

Diagnostic trouble code B1841 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 B1841.

Fortunately, B1841 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

B1841 Trouble Code For Specific Cars

B1841 Saab 900 Ignition Run/Start Circuit Open
B1841 Morris Cowley Brake Pedal Input Circuit Ground Short
B1841 Mercedes E 270 ABS Power Relay Output Open Circuit
B1841 Leyland Austin Theft Deterrent Fuel Enable Signal Not Received/ B+ Supply To VCRM A/C Circuit Malfunction
B1841 Durkopp 40 Hp Immobilizer/ECM Communication Error
B1841 Jensen Sp Seat Driver Recline Rearward Switch Circuit Short To Battery
B1841 Porsche Rsk Fuel Pump Speed Primary Circuit Malfunction