Chevy 2500HD P0300 code - Engine ODB2 Fault Codes


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Chevy 2500HD P0300 code

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Auto Repair Home>> Automotive Repair>> Engine ODB2 Fault Codes

the3brittons
New User

Aug 26, 2011, 7:47 PM

Post #1 of 4 (6725 views)

Chevy 2500HD P0300 code	Sign In

I have a 2001 Chevy 2500HD 6.0L with 167,000 miles. At highway speeds the service engine soon light comes on when on flat ground or going down hill. When laboring the engine going up a gradual incline or steeper hill it goes off. I have changed the plugs and wires but that did not help, the engine seems to run fine and I don't notice it missing at all. I just wanted to see if anyone had suggestions for me before my appointment with the repair shop Monday morning.

Thanks. Jeff

Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 27, 2011, 3:05 AM

Post #2 of 4 (6699 views)

Re: Chevy 2500HD P0300 code	Sign In

The "check engine" light is an indicator for a system that monitors many electronic functions in the system, also called the "malfunction indicator lamp" (MIL). It can come on for any of hundreds of different causes from any of the systems that the computer monitors. Some are very important and can lead to further component or engine damage and some are emissions related not as serious but still a problem and need to be repaired.

Your first step is to have the computer scanned to retrieve the trouble codes that were set when the check engine light came on. Those codes will give you specific information about what the computer saw and will get you pointed in the right direction to find your problem.

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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.

the3brittons
New User

Aug 27, 2011, 8:38 PM

Post #3 of 4 (6683 views)

Re: Chevy 2500HD P0300 code	Sign In

I cleared the P0300 code after I changed the plugs and wires, then took it out for a drive again. It did the same as before, the light flashes under no load, and goes off when under a load at highway speed (60-65 mph or more). got back home and pulled P0300 code again. Not noticing any kind of missing, engine seems to run fine.

Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Aug 27, 2011, 9:52 PM

Post #4 of 4 (6673 views)

Re: Chevy 2500HD P0300 code	Sign In

More than likely it is setting a false P0300. Swing into a shop that has a high end scan tool or Tech 2 and have them perform a crank variation relearn. See if that solves your problem.

Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

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