2009 ML63 P0171 Check Engine (Need Help)
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Joined: May 2007
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2009 ML63 P0171 Check Engine (Need Help)
Last night when I started my car after work, the check engine light came on. Ran the codes at Autozone, and it was P0171. (System too lean, Bank 1).
Bought some MAF cleaner, and cleaned both of the MAF sensors.
Left the car overnight. This morning I drove the car to Autozone, thought they'd clear the code for me, apparently they aren't allowed to, so I brought it home, and disconnected the battery for about 30 minutes.
Started her up, and the check engine light is still on. Didn't clear at all, it was on at start up.
Any ideas what I should look at next? I assumed disconnecting the battery would clear the code right away, and then after some miles if the MAF cleaning didn't fix the problem, it would come back on, and then I'd look at replacing MAF, vacuum leak, or 02 sensor.
I guess my first question is that, should the Check Engine been cleared when I disconnected the battery and then started the car again? And then, what else should I look at next?
Also, the night before this light came on, I installed LED license plate lights, with a resistor, no bulb out warning with the resistor in. That's the only thing that "changed" on the car prior to the check engine coming on, but I doubt the lights/resistor caused this.
Bought some MAF cleaner, and cleaned both of the MAF sensors.
Left the car overnight. This morning I drove the car to Autozone, thought they'd clear the code for me, apparently they aren't allowed to, so I brought it home, and disconnected the battery for about 30 minutes.
Started her up, and the check engine light is still on. Didn't clear at all, it was on at start up.
Any ideas what I should look at next? I assumed disconnecting the battery would clear the code right away, and then after some miles if the MAF cleaning didn't fix the problem, it would come back on, and then I'd look at replacing MAF, vacuum leak, or 02 sensor.
I guess my first question is that, should the Check Engine been cleared when I disconnected the battery and then started the car again? And then, what else should I look at next?
Also, the night before this light came on, I installed LED license plate lights, with a resistor, no bulb out warning with the resistor in. That's the only thing that "changed" on the car prior to the check engine coming on, but I doubt the lights/resistor caused this.
Thread Starter
Junior Member
Joined: May 2007
Posts: 23
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Update:
I rented an OBD II scanner from Autozone and cleared the code myself.
Drove 340 miles this weekend, and the Check Engine light has not turned back on. I'm not sure why the code wouldn't clear after having the battery disconnected for 30 minutes, but it cleared with the OBD II.
Looks like for the time being, cleaning the MAF sensors was the trick.
I rented an OBD II scanner from Autozone and cleared the code myself.
Drove 340 miles this weekend, and the Check Engine light has not turned back on. I'm not sure why the code wouldn't clear after having the battery disconnected for 30 minutes, but it cleared with the OBD II.
Looks like for the time being, cleaning the MAF sensors was the trick.
