P291B Diagnostic Trouble Code

P291B 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 P291B diagnostic trouble code may include:

Corroded or damaged connector
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Lack of power
Diminished fuel efficiency

Possible Causes :

Faulty IMRC actuator/sensor
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness.

Process Tips

Diagnostic trouble code P291B 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 P291B.

Fortunately, P291B is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P291B Trouble Code For Specific Cars

P291B Porsche Cayenne Type 9pa
P291B Vauxhall Monaro Pressure Control Solenoid B Intermittent
P291B Oldsmobile Aerotech Cylinder 6 Injector Circuit High
P291B Plymouth Road Runner Evaporative Vac Solenoid Circuit Malfunction
P291B Simca Aronde Interior Fan Control Circuit Open
P291B Tvr Tamora Power Steering Failure
P291B Mercedes-benz 240 Air Bag passenger Circuit Open - Loop #2