How to perform a trip drive cycle

MILKBONE15

MEMBER
CHEVROLET SILVERADO

HI
I have a 2000 silverado V8 with 160000 miles on it.
I think the knock sensor is bad but I want to do a trip drive cycle first to reset the PCM. How do I do this?

Sunday, February 11th, 2007 AT 10:39 PM

5 Replies

SERVICE WRITER

MECHANIC
9,123 POSTS

I assume you have cleared the codes?

And you want to do the drive cycle to run the monitors thru their self tests?

Why do you think the knock sensor is bad?

What symptoms do you have?

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Monday, February 12th, 2007 AT 3:46 AM

MILKBONE15

MEMBER
3 POSTS

Well it has a hard start problem and the scaner shows that the knock sensor is sending a code some of the time but not enough to turn on the "serv eng soon" light. The only code that was showing up before clearing the code was a bad MAF sensor which has been replaced and the engine runs much better since once you get it to start. What else could be wrong?

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Monday, February 12th, 2007 AT 7:58 AM

SERVICE WRITER

MECHANIC
9,123 POSTS

Is it that you have to crank it for a long time? Does it start hard ALL the time.

Do this:

Cycle the ignition key. Turn it to the on position for 5 seconds and then back to the off position for five seconds. Do this 3 or 4 times when you believe the problem should happen. After the 4th time, crank it.

Did it start right up?

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Monday, February 12th, 2007 AT 5:20 PM

MILKBONE15

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3 POSTS

Did not seam to make any difference. It starts right up in the morning then driven to work, but at lunch time it is hard to start. I have to keep the starter turning longer than I should but don't have to push the gas to keep it running. Also the service engine soon light is back on and the only code is PO332.

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Wednesday, February 14th, 2007 AT 2:37 PM

SERVICE WRITER

MECHANIC
9,123 POSTS

I would go after the code if it were me. Check your email for some goodie to help, contact me if there is anything you need other wise. I can't help but wonder if the intake manifold is leaking.