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P0991 Engine Trouble Code

P0991 Engine

When you check engine light came on code P0991 the reason should be . However your vehicle's manufacturer may have a different definition for the P0991 OBD-II Diagnostic Powertrain (P) Trouble Code. So you should chech it on our car models.

When the check engine light comes P0991 code on the first you should check is the gas cap. Pull over, retighten it, and take a look at the cap to see if it has any cracks in it. Continue driving and see if the check engine light turns off. Alternately, you can purchase a gas cap for about $3 at an auto parts store. All you need to do is take the old one off and screw on the new one. If you've already made it to the store, you might as well just replace it. While not car-threatening, it's good to take care of this right away to improve gas mileage.

P0991 Code Meaning :

P 0 9 9 1
OBD-II Diagnostic Powertrain (P) Trouble Code For Engine Intake Valve Control Solenoid Circuit Low Injector Circuit Malfunction - Cylinders Cylinder 4 Contribution/Balance Fault Glow Plug/Heater Circuit 'A' Malfunction

The oxygen (02) sensors on your car measure the oxygen in the exhaust to determine how rich or lean the ratio of fuel and air are in the cylinders. Optimizing this mixture means better fuel economy and fewer exhaust emissions.

P0991 OBD-II Diagnostic Powertrain (P) Trouble Code Description

P0991 engine trouble code is about Glow Plug/Heater Circuit 'A' Malfunction.

Reason For P0991 Code

The reason of P0991 OBD-II Engine Trouble Code is Injector Circuit Malfunction - Cylinders.

P0991 DTC specifically refers to the camshaft (cam) timing. In this case, if the cam timing is over-retarded, the engine light will be illluminated and the code will be set.