P149D Diagnostic Trouble Code

P149D 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 P149D diagnostic trouble code may include:

Reduction in engine performance, especially at low RPM levels
Vacuum leak on the engine
Diminished fuel efficiency
Engine surge

Possible Causes :

Rusty exhaust systems, cracked exhaust manifolds or damaged or missing gaskets or donuts will cause air leaks.
An air leak forward of the DPF will change the sensor readings resulting in the code
Dirty air cleaner element Damaged DPF

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. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve. Look for damage to the tank indicating impact that may have damaged the fuel pump or sender.

Process Tips

Diagnostic trouble code P149D 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 P149D.

Fortunately, P149D is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P149D Trouble Code For Specific Cars

P149D Austin A40 Autolamp Delay Increase Circuit Open
P149D Daimler One-o-four Heated Backlite Relay Circuit Failure
P149D Lancia Fulvia Speed Wheel Sensor Rear Center Input Short Circuit To Battery
P149D Isuzu Aska SCP (J1850) Invalid or Missing Data for Steering / Steering Wheel
P149D Chrysler Aspen Engine Oil Temperature Sensor Malfunction
P149D Vector M PRNDL Reverse Input Open Circuit
P149D Chevrolet Master EGI Functionality Test Failed