I had the "Service Engine Soon" light come on my 2000 Lightning. I have about 15 K miles on it. It also has a Bassani full exhaust, ProM mass air, and chip so I don't want to take it to the dealer unless absolutely necessary. I can reset the light by disconnecting and reconnecting the computer but it came back on after a few driving cycles.

I understand that the warning relates to emissions monitoring. Could this be a failure in one of the O2 sensor?. Are there any fault codes available in any special diagnostic modes that can be activated?

Any input would be appreciated!

 

TXFLOOD,

Indeed it _could_ be an O2 going bad (there are 4 O2s on our trucks...2 for monitoring the engine and 2 behind the cats to monitor their function) or a cat going bad. This has happened on my '96 Cobra.

But, this is just a guess. It could be something else.

How does the truck run?



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Wes Tarbox
90 LX 5.0 (10.69 @ 134.7)--597rwhp/590rwtq
96 Cobra (12.63 @ 114.5)--390rwhp/441rwtq
99 Lightning (13.20 @ 103.3)--362rwhp/444rwtq
00 Expedition XLT 5.4
http://members.aol.com/Wa2fst/index.html

 

TXFLOOD, My L did the same thing as you were describing and it turned out to be a bad O2 sensor. The dealership told me that it was not heating up properly. Also the guy at the dealership was talking to me and stated that he read in a magazine that a chip and filter would add 50 hp to the new L's. I told him I knew that because I had already installed them but took them out before bringing them in for service. He told me not to worry about it and if I had to bring it again for service to leave the chip and filter in it and bring it on in. He said it really didn't matter if I had a chip and filter installed or not. I guess it all depends on the dealership I guess.

HANKFAN

 

check to make sure you arent loosing coolant. An intercooler leak can foul the o2 sensors and cause the light.

 

TXFLOOD - Have you fueled up the truck while the engine was running? Have you checked to see if the fuel tank cap seals tight? Sounds pretty stupid but I know from first hand knowledge that either one of these can cause the check engine light to come on. It hasn't happened on the L yet but doing either one of these will trip the light on my 99 Exploder everytime.

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Rick - Hwy_2_L@HotMail.com
Friends don't let Friends drive Chevys
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TXFLOOD
Check all the O2 connections and then pull the pcm and check all the pins inside the unit. After you check the gas cap, it will do the same thing. If you come up empty, have dealer check the O2's.

 

Wes,
I seems to run fine. The dealer can't look a it for a couple of weeks, so now I'm impatient and want to see if it's some thing simple or at least confirm the problem.