CEL and TRAC OFF lights on

2018 Tacoma V6 — CEL/TRAC OFF After Engine Bay Wash

My 2018 Tacoma V6 currently has 60,500 miles. I recently changed the front and rear differential fluids and did a routine oil change. The truck was running perfectly with no warning lights on the dash.

After the maintenance, I decided to wash the truck, including the engine bay since it was a bit dusty (this wasn’t the first time I’ve cleaned it). I let the engine bay air dry for about 3 hours with the hood open, and then another 2 hours with the hood closed.

Later that evening, I went to start it up and noticed the CEL (Check Engine Light) and TRAC OFF lights were on. The engine started but stalled after about 10 seconds. Headlights and all accessories stayed on. I started it again and tried slowly driving about 30 yards, but it stalled again after I gave it a bit of throttle. I started it a third time and was able to reverse it back into the garage. While stopped, I tried revving the engine, but it struggled and then shut off.

When I scanned the truck, I got the following codes:

• P0201
  
  
• P0202
  
  
• P0205
  

These all point to "Injector Circuit/Open Cylinder" issues.

After resetting the battery, the codes reappeared within a minute, but P0202 was replaced with P0204 this time.

I’ll be away for the next two weeks and won’t be able to check on the truck until I return. Just wanted to get some input on what I can look into once I’m back, before I potentially take it in to Toyota.

 

Check for mice-chewed wires under the intake manifold. The water from the wash probably caused shorts with the exposed conductors (from chewing).

 

Will be doing that when I get home since I already planned to replace the spark plugs.

 

I had a similar situation with intermittent P0202 CEL and limp mode, after one dealer replaced the #2 fuel injector, the problem reappeared months later, another dealer determined it was a broken pin in a wire harness adapter which I assumed happen after i did the fuel pump recall on my 2018 which occured a month earlier, the CEL was sometimes month apart. Stressful year, but after Pin replacement in the wire harness which they didn't specify, I was relieved and has been running flawless for several years now.

 

Good to know. I'll be checking the pins on the injectors wire harness. It's just weird that I have the codes for three injectors, and after resetting my battery the code P0202 disappeared but P0204 appeared.

 

If you didnt have an issue prior to this, probably just water in the connectors.....
Best case of an unfortunate lesson learned...

 

Definitely sounds like something in the wiring, etc.

 

Fingers crossed that that is it. Hopefully the 2 weeks I'm gone is enough for whatever got wet to dry up. The only rodent problem we had was a rat making it's way into the cabin air filter, getting stuck, and dying in there.
Lesson learned for sure, won't be hosing down the engine bay...maybe just a light mist and wipe down.

 

^The connectors under the hood have weatherpak seals. Did you use a pressure washer or just a garden hose? A garden hose won't cause water ingress unless there's pre-existing damage (like from rodents).

I stop by a self-serve car wash on the way back from every wheeling trip and hose down the engine bay to wash away mud and dirt. Never had an issue.

 

Used garden hose with a shower nozzle so it wasn't anything high pressure. I've pressured washed the engine bay before and even used brushes to really clean it so maybe something came loose from that time and got wet during this wash.

 

light mist & leaf blower....
shop vac, compressed air, etc...
as far as drying out on its own once its in there, wishful thinking, but, but, maybe...

 

To my knowledge, water does not conduct well enough to mess with any 12v system circuits. High voltage spark ignition or any coils can certainly be affected by water, plus seems likely that 5v (shielded computer) signals could be affected. Despite the above, if the wire insulation is compromised, then the addition of moisture could be the last straw, but the damage is the fault, not the water.

I cannot envision why wetting would be the last straw for any loose terminal situation; water would slightly improve the connection, not reduce it.

If drying things out fixes your problem, I would follow by wetting small areas with a spay bottle, to try to narrow down the breach, starting with coil housings (like in an ignition coil or injector), but then expand to anything else. Ward off getting stranded while driving in pouring rain. I wash under my hood with a power washer at the car wash, and drive away; never had an issue. This convinces me that you have a problem somewhere, and the water just makes it announce itself. Something needs fixing, and you are fortunate to be given a chance to find it, before it turns into a tow bill.

 

****UPDATE****

Got home from vacation. First thing I did was another battery reset by removing the positive side for 10 minutes. While waiting, I checked the wires to and from the fuel injectors for any play or damage and there's none. Checked the fuses for the injectors and they're solid. Replugged the positive of the battery and let the truck idle to see if the CEL comes on but it didn't. After the truck was up to temp, I went for a drive and the truck is driving like normal.