Code U1000 not communicating, new coils burned up

CORVETTEAL

MEMBER
2005 NISSAN FRONTIER
4.0L
6 CYL
2WD
MANUAL
150,000 MILES

Truck quit running. Took to two shops, one said he couldn't figure it out. No spark? Or fuel. Fuel pump runs with direct power. ECM won't communicate. First shop gave up, second shop replaced two coils that promptly burned themselves up without running. I understand it may be a ground issue but what about the coils burning up. I told it needs an ECM but I have also read there is a relay for the coils that I have conflicting information on whether the condenser coil is in the fuse box or taped up in the main wiring harness. I am willing to replace ECM but don't to burn it up along with the new coils. Where is the ignition coil/relay and what grounds can I check? Thanks.

8 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Couple questions first. You have coil on plug ignition coils with integrated power transistors. That means the primary and secondary windings are in the coil. Do you have one specific coil that is failing or was this different ones that failed?

The most common things to cause this type of coil to fail is voltage spikes or faulty grounds as you stated. So we need to find out if the F16 ground at the front of the engine is intact. They all share the same ground so we need to find out if there were multiple coils failing.

Clearly this could be other things but I would start with this and go from there.

The ECM is most likely not causing the coils to fail as it only sends the low voltage signal to the coil where it interrupts the signal to cause the high voltage spike. It has happened but I would suspect the ground issue so let us know what you find with that and we can go from there. Thanks

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Tuesday, September 1st, 2020 AT 5:24 PM

KASEKENNY

MECHANIC
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One other thing, did they change the spark plugs? If this was the same cylinder that the coils failed, it is possible that the worn out spark plug is causing high resistance in the circuit and the high voltage spike of the secondary side of the coil is escaping through the internal transistor of the coil which will cause it to fail. Just another thought. Let us know if these are different cylinders. Thanks

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Tuesday, September 1st, 2020 AT 5:29 PM

CORVETTEAL

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I did check the grounds. The are attached. I removed them, cleaned and reinstalled. There were two failed coils. One of the two replacements, overheated and bubbled up. This was at the shop. Now I cannot get any communication with ECM U1000. No fuel, no check engine light, no security light (don;t think this truck has theft), fans come on and stay on. Went through all the ohm checks at the ALDL. 60 ohms, checked the IPDM ohm;s in cavity 39 and 40 120 ohms. Looks like the ECM is dead but I keep reading about an elusive condenser ignition coil - a resister in the wiring harness but cannot find mention of it in Mitchell. (Yes coil over plug 4.0 V6). I do not know if the plugs were changed as they gave up and didn't charge me so likely not. I show a general part # for the condenser coil as 28351-89902. Thanks

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Tuesday, September 1st, 2020 AT 5:34 PM

KASEKENNY

MECHANIC
18,907 POSTS

So I am going to join the search on this condenser. I attached the info about it but there is no location. I would suggest finding the ground for it on the front of the engine F16 and tracking it back to see if you can find it. Clearly we need to test resistance for it as shown in the test.

However, I agree that the ECM appears to be failed. Let me know if you can find it and we can go from there. Thanks

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