reviving an old thread but this happened to me twice in a year's time. first time I swapped the module and left it overnight then it started and ran fine for several months. recently it's been happening a couple times a week and luckily I was able to clear the code and restart and it would run fine but yesterday the P1606 popped up and WOULD NOT CLEAR. took a Lyft to a nearby dealership where they had 1 relay left in stock, swapped it in and still nothing. limped it home at 5mph and let it sit overnight and now it runs like nothing ever happened. I'd really like to know the definite fix for this. even though I have AAA I'd rather fix it once and be sure.

tl;dr new relay + sitting overnight fixed my P1606

Sounds like a wiring or sensor problem. The FSM (link in my sig) will have troubleshooting procedures.

thanks. downloaded most of it the first time i had this issue.

sidenote, after i replaced the relay last week it seems my car runs differently, the exhaust sound is deeper and it feels like the car runs smoother? is this a placebo or can the VVEL module really make that much of a difference?

I have two guesses:
1) The new module is allowing the engine to run properly again, ie, that's the way it's supposed to sound.
2) The new module has slightly different programming.

Im going through the same thing. Swapped module and relay out yesterday with no luck. Its been sitting in the garage overnight so hopefully itll start fine later this morning

Check your grounds for vvel. Wire brush and make sure they are tight on the chassis.

My dealer says it's the wiring harness. They wanted 8k between parts and labor. There's 2 harnesses they wanted to replace. The engine harness and the body control harness. Talking to the mechanic himself he said he thinks it's just the body control harness but he had to run it by some area Nissan engineer who told him replacing both is the only way to garuntee it's fixed since I kept coming back with the same issue.

Is the ground right behind the relays and next to the fuse box?

Just for anyone having to remove the VVEL module, you dont have to use a tiny screw driver. On the connector itself is an orange lever that you have to pull. But before you can pull it, theres a little tab close to the top of the lever handle that needs to be pushed in to release the lever handle.

The 4 tabs described above catches on grooves of a plastic retainer thing that slides up and down along with the lever.

Been getting P1606 lately. Sometimes I am able to reset it and the car runs fine for weeks. Then it randomly pops up again. I ordered a new relay and used VVEL control module. Going to pop it in this weekend. Do I need to reprogram the module or do anything else with it besides plug and play? It is coming from a used car so I wouldn't imagine needing to. Super frustrating.

Will report back once it's done.

Its plug and play. Youll have to reset the ECU, idle relearn, etc..
Make sure the relay box sits securely on the relay box bracket and it doesnt have too much play in it, and also, the little clips on the side that holds the relays make sure they arent broken. That can cause the relays to jar loose.

Thank you!

Just wanted to give an update. So after spending 15 minutes swapping out the VVEL control module with the one I got from ebay for $60, I did a full ECU reset and fired it up. Lights off and the problem hasn't come back for about a month now, ~500 miles.

Such a helpful thread!
 

Hello all, pleased to meet you.

Ive been rebuilding a salvage 2014 Nissan 370Z for the past year and it's just about done. Ive been following this thread for about a month but now that Im authorized I can chime in. I have 4 codes (P1606, U1024, P0112, P0102) as well as many other minor hiccups with drivability, but those are simply a matter of turning a wrench.

The car was running OK with no engine lights until about a week ago when it died at a left turn redlight on the highway... super limp mode was engaged... After getting it off to the side and letting it sit for less than 15 minutes it started up with no problems. No engine light. Ive replaced my VVEL module previously and recently replaced my VVEL relay.

I have a working theory that the issue isn't the VVEL module or relays at all but is in fact the IPDM module supplying inconsistent power to the VVEL module and destroying the components. Im going to go over my IPDM with a multimeter if replacing the relays and VVEL module again (+ better waterproofing) doesnt work.