1998 Chevy Silverado Engine Light Not On | Won't Pass Emissions

1998 Chevrolet Silverado 1500 4x4. Engine size = 5.7L Repairs for this problem: checked for loose or broken wires,replaced the bulb,and replaced the cluster panel.
Question: My truck wouldn't pass emissions because the MIL wouldn't come on when the ignition was turned on. The bulb was burned out. I replaced the bulb, it still didn't work.

I can trigger a check engine light scan code and it will come on. Once i clear the code and turn on the ignition on it comes on. I start the engine, turn it off, turn the ignition back on it doesn't come on.The reason i replaced the cluster panel, i thought the problem might be in the IPC board. It worked like it should when i installed it, until i started the engine.  Please Help!

Answer: The check engine light is controlled by the PCM. It grounds that circuit. With that said, I think what you are describing is a strange characteristic of this and other GM trucks. Have seen this many times. When you first start the truck, the light is on, shut it off, then turn key back to ON position, light is not on like it should be. What you need to do is when you turn off the key, leave it off for almost one minute. Quickly turning back on causes the condition you describe. Even if leaving it off for 10 seconds or so- same result. The fact that you can cause a code which turns on the light means that the IPC, bulb and PCM are functioning normally. I think the bulb replacement fixed the original problem, but now you think look so closely at its operation, you see think characteristic as a problem- which it is not. Find a friend with a similar year and model and compare.

Knock Sensor Location

2002 Chevy 1500 Engine Size : 3.5 1500. Question: Were is the knock sensor on the motor, cant find it.

Answer: I'm going to assume you meant the 5.3 engine, since there is no 3.5 offered in a Silverado. The knock sensors are located underneath the intake manifold. You have to remove the intake manifold, which is not that difficult of a job, and then you can access the knock sensors. There are two that are mounted in the lifter valley cover under the intake. You should replace them in pairs. Be sure to route the wiring harness and connectors correctly for the knock sensors, otherwise you might crush or pinch the wires when reinstalling the intake manifold.

Chevy C/K Truck Multiple Misfires

1998 c/k Chev 1500 4+4 5.7 L Vortec. Question: intermittent misfire on #2,4,6,8 cyl,s more noticeable when wet,changed cap and rotor, wires, plugs, intake gaskets, also code P0404 EGR out of range, also changed out, thanks for any help.Bill

Answer: Misfire on one entire bank, with all these parts replaced, makes me think that you have a partially plugged catalytic converter on that side. This would also explain the EGR code, since the exhaust would be backing up into the system. You would need to have a backpressure test done to confirm that. Also, if the engine looses power under hard acceleration when the engine is hot, this would also indicate a plugged convertor.

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Comments (7)
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  • Guest - Countryman

    2006 1500 5.3 Suburban.
    No check engine light. I took cluster apart and shined a light thru the face cover and no check engine light on it.
    I took it to get inspection and it failed because light didn't come on when ignition was turned on.
    Could check engine be in message display or only when needed?
    Is it possible I don't have a check engine symbol.
    Lights in instrument panel are non replaceable LED .
    I bought vehicle a year ago, first time having it inspected.

  • Guest - Chad

    In reply to: Guest - Countryman

    Yes, the engine light warning can also be displayed in the information center, but there is definitely a check engine light indicator or bulb location that comes on when there is a problem or when the key is first turned on.

  • Guest - Pamela martin

    I taken my car yesterday for the emissions sticker my car won't pass because the engine won't get hot

  • Guest - Pamela martin

    In reply to: Guest - Pamela martin

    Sorry it's a 1998 buick lasabre

  • Guest - Gary Poteet

    What is the procedure for replacing the ignition switch?

  • Guest - Gary Poteet

    I really appreciate you taking the time to answer my question about the MIL not coming on when I turn the ignition on. But as far as leaving the ignition off for a longer period of time, that doesn't work either. Maybe you misunderstood what I was trying to say. The only time the MIL will work is when I trigger a code and then clear it.I turn the ignition, the light will come on, I start the engine, turns it off and wait overnight and the light will not come back on until I trigger a code again. If the problem is in the PCM could it have damaged the PC board on the instrument cluster?

  • Guest - tech

    In reply to: Guest - Gary Poteet

    OK. I see. Thought you were just shutting off then turning on. Well, then I would have to say this is a problem with the PCM. It controls the light. Unless you have other lights that do not come on, then I would suspect a bad ignition switch. Without having the truck in front of me with a scanner to look at data, I would not just put a computer in it, though, that is an expensive guess.