early 99 engine into a 2002 truck, check engine light with no codes?

[Matthews]

Hey guys, I swaped an engine from an early 99 truck into a 2002 chassis and now I always have a check engine light. There are no codes though, at least with the code reader I am using. I am using the stock 2002 computer. The engine seems to run well without any problems.

What could cause the check engine light?

[None2Slow]

Before you actually start the engine, when you turn the key to on, does the light come on for a second, then turn off? Or is it on the entire time?

[Matthews]

I think it's on the entire time. Doesn't a check engine light normally come on when you switch to run then stay on until the engine is running?

[None2Slow]

If I remember correctly, when you turn it on, it should light up, then when you start it, it should stay on for a second, then turn off. Then if there are problems, it should light back up. I need to go out and see what mine does. I know that they are supposed to turn on with the key as a way for smog techs to know that the light works and you just didnt take out the bulb. I've see that more than 1 time working there.

[Matthews]

Does anyone have any insight on this? How can I scan to find out why the light is on?

[dieselcrawler]

Did you use the intake spyder from the E99 trk? If you did, the lack of intake air heater could set a code... need more details on what was used from the later motor or older one.


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[Matthews]

The entire 99 system was used, so there is no intake air heater. Should that code show up with a regular scanner? I am not seeing any codes.

[dentexpowerstroke]

A lot of scanners won't read the codes on our trucks. You may have to go to continuous memory to see the codes. AIH is a soft code, won't set cel. Is the WTS light coming on as usual?

[Matthews]

The wait to start light comes on and does seem to work properly. Truck starts well, even in the cold. How do I go to the continuous memory for the codes? What scanner do I need?

[dentexpowerstroke]

The one at oriellys can do it if you go to the continuous memory test, its usually with the koeo and koer tests. I was asking about wts light to make sure the pcm isn't fried and just throwing the cel.