QuestionQUESTION: My Santa Fe has 76,000 miles. V6 2.7 engine. The engine light came on. My husband took it to Auto Zone to have the code read. They said it read as Fuel Metering System. We did not get a code number. Subsequently the light went off. We went ahead and replaced the gas cap, but now the engine light is back on one day later. It still runs fine. Any suggestions? Is is possible that it is bad gas? I appreciate your help.
ANSWER: Unfortunately, "fuel metering system" doesn't give me much information. That could apply to many things in the fuel management system. Since the lamp is back on, return to AutoZone and have them read the codes again, but make sure they understand you want the code numbers so you can look them up yourself. Since they're using a generic scan tool, it may not provide the proper definition for codes that are specific to Hyundai (anything beginning with P1 or P2).
Since the vehicle is running normally, it's doubtful that it's bad gas. In fact, there are pages and pages of things that could turn on the check engine lamp. When you get the code numbers from AutoZone, follow up with them here and I'll advise you on how to diagnose/repair the issue.
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QUESTION: The error code is P1166. Is this something that we could fix on our own or do we need to take it to the shop? Thank you for your advice.
AnswerP1166 indicates that the computer is unable to make enough adjustment to the injector on-time on bank one (firewall side) to maintain proper emissions as determined by the upstream oxygen sensor.
In most cases when I've seen this code, the problem is the oxygen sensor. A scan tool is an effective tool in performing this diagnosis. With the scan tool, it's possible to compare the oxygen sensor readings and fuel trims (injector on-time adjustment levels) on the two banks of the engine. If the values are out of kilter on only one bank, then the upstream oxygen sensor on that bank is the likely culprit.
If, on the other hand, both banks show similar abnormal values for the oxygen sensor or fuel trim readings, you're more likely to have a large vacuum leak or a stuck open purge control valve, thus introducing more unmetered air or fuel into the engine than the ECM can compensate for.
If you wish to take a guess, the oxygen sensor has good probability of fixing the issue. If you'd rather be sure, you should take the car to a good driveability shop for diagnosis.
