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Aug 4, 2014 | 08:51 PM

94wyatt95

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Check engine light

I have a 95 f150 351 with an auto trans. My truck runs fine, but all the sudden it had a check engine light come on. I know it didn't have any memory codes because I hade clear the codes when I baught the truck 3weeks ago. The koeo codes are: 122, 126, 128, 172, 327, 334. I know what they all mean. I just don't understand why they would all show up at one time. Any thoughts? Thanks.

Aug 4, 2014 | 10:28 PM

eakermeld

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From: South Central,MO

I do believe a major vacuum leak would cause all of those at once.

Aug 5, 2014 | 03:18 AM

94wyatt95

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I will check everything out when I get the chance. I would think it would run rough, but stranger things have happened. I also cleared the codes and I'll wait for them to come back. Thank you.

Aug 5, 2014 | 08:00 AM

rla2005

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From: Kentucky

Quote:

Originally Posted by eakermeld

I do believe a major vacuum leak would cause all of those at once.

I disgaree....a vacuum leak will not affect the TPS output (Code 122). Same for many of the other codes.

Aug 5, 2014 | 08:03 AM

rla2005

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From: Kentucky

Many of those codes come from sensors that use the same VREF signal from the CPU. Use a DVM to measure that signal at any one of the sensors. The TPS is easy to gain access, start there. It should measure +5 VDC +/- 3%

Aug 5, 2014 | 09:01 AM

subford

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From: Easton,Ks

X2^^
Does look like the electrolytic capacitors have had it in the PCM.
So bad computer or change out the electrolytic capacitors.

Aug 5, 2014 | 03:50 PM

94wyatt95

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Well the codes haven't came back. Maybe it was a fluke, but if I see them agsin, that will be the first place I check. Is it the computer under the dash your talking about? Thabks

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Aug 6, 2014 | 06:12 PM

94wyatt95

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Thanks for the picture. I got code 172 back today. I couldn't find a vacumm leak any where. Could the 02 sensors be reading bad. What should I look for now?

Aug 6, 2014 | 09:20 PM

#10

rla2005

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From: Kentucky

Quote:

Originally Posted by 94wyatt95

Thanks for the picture. I got code 172 back today. I couldn't find a vacumm leak any where. Could the 02 sensors be reading bad. What should I look for now?

The capacitors in the computer (PCM)