I have three car codes come up and I wanted to know what maybe the problem. The codes are p0170, p0449, and p0455
My car has 193000 miles.
My car has an automatic transmission.
Diagnostic Trouble Code P0170 means that your engine computer (PCM) has had to adjust the fuel trim (fuel supply), high or low, but to the extent that the adjustment is out of the "normal" range. This adjustment that the PCM attempts is a consequence of an underlying fault, for example in a component or part, and so once the code is set the repair strategy is simply to identify the underlying fault and repair it. In the event of a too high fuel trim adjustment, the underlying fault could be, for example, a weak fuel pump, a clogged fuel filter, or a faulty fuel pressure regulator. In the event of a too low fuel trim adjustment, the underlying fault could be, for example, any condition that causes the engine to run rich such as a faulty mass air flow sensor, manifold absolute pressure sensor, or a faulty fuel pressure regulator. Technically, although a faulty PCM (the powertrain control module itself) can account for these codes to set that would be an exceptional circumstance and so is not considered until all other more likely causes are ruled out. When the mechanic performs the diagnostic on your car, he will use an advanced scan tool to see if the fuel trim is high versus low, so that the appropriate potential faults are focused on first.
The other two codes you have reported relate to faults in the evaporative emissions control system and are not as critical as the Code P0170 which indeed should be addressed and resolved promptly because of the potential for engine and/or catalytic convterer damage. Code P0449 means that the evaporative emission control system vent valve or solenoid has a malfunction. The ECU detects this fault and causes the Check Engine Light to be illuminated on the dashboard. Code P0440 indicates a large leak in the EVAP system, not a liquid fuel leak, but rather a leak in the vapor recovery system. Sometimes, erasing the code and re-tightening the gas cap will resolve that code. If not, the EVAP system has to be leak tested using a special very low pressure (1 or 2 PSI) portable smoke machine.
To get all these Trouble Codes addressed, the recommended service is a check engine light diagnostic. At the conclusion of that diagnostic, the Mechanic will let you know much more specifically what component(s) or systems need to be repaired and what the cost will be.
Have a car question? Get free advice from our top-rated mechanics.
Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing