Service engine light does not come on when you turn ignition?

Hi,

The check/service engine light won't prevent the engine from starting. Does the starter engage and turn the engine? If it does, try this. See if the engine starts with starting fluid. If it does and then stalls, we know its fuel related. If there is no change, check to see if there is spark to the plugs.

Here is a link that explains how it's done:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

Next, if the starter doesn't engage, let me know if anything happens and if other electrical components are working.

Take care,

Joe

Hi,

The starter engages and there's spark on plug, but the injector pulse is missing because there's no service engine light to complete the ignition circuit. I have witnessed it on many vehicles. The only way I can convince you is that if you know any circuit that can make service engine light to put on, tell me and I will come back to tell you that the problem is solved.

Hi,

If you just want power to the service engine light, any circuit can provide the power you need. I'm not sure exactly what you are looking for.

Does the air bag light, brake light, seat belt light, oil pressure light, and so on turn on? They all get power from the same source as the CEL. If none of those work and the fuse is good, remove the fuse and take a jumper wire to the feed side of the fuse to see if it helps.

See pic below.

Let me know.

Joe

Does the air bag light, brake light, seat belt light, oil pressure light, and so on turn on? Yes, they all turn on except CEL, I ground the ECM terminal 18 and turn ignition on and CEL comes on and I remove the wire I used to ground it and it turn off while the ignition was still on.
How do I test to see if the ECM is grounding the circuit or how many volts should the ECM use to provide for grounding it let me used DMM to check it?

If you want to check right at the ECM, check to see if there is continuity to ground when the light should be on. Since the other components are working, the CEL should be getting power as well.

Let me know.

Joe

Check to see if there is continuity to ground when the light should be on. I didn't understand, do you mean I should probe the terminal 18 of ECM connector and ground using DMM or Instrument cluster connector and ground while ignition is on?

Hi,

If there is a ground issue, it's the result of the ECM and not the cluster. So, in this case, I would check for ground at the ECM. Yes, you can use a multimeter. You can even use a test light if that is easier. Simply connect one side of the test light to the positive side of the battery and the other end to terminal 18 and turn the key on. If a ground is provided, the light will turn on.

Let me know.

Joe

I have done it before.
Note: I ground the ECM terminal 18 and turn ignition on and CEL comes on and I remove the wire I used to ground it and it turn off while the ignition was still on. But I will still use the test-lamp, and do it as you said, probing the positive side of battery using one terminal of test-lamp and the other to ECM terminal 18.

Have you checked the ECM ground? Run a ground between the ECM body and the battery negative and see if that changes things.

Based on what you are saying, if it requires you to ground the ECM at pin 18, it sounds like it has failed.

Let me know.

Joe