HELP! Check engine light does NOT come on

Hello everyone, Thank you in advance for any advice you might be able to give me with my issue.

After looking for a truck for months and being disappointed with every test drive, I found my 2006 tundra V8 4.7 on Facebook marketplace. I was committed to having it inspected by a mechanic before purchasing, but I was far away from my home and was worried great opportunity would be taken by someone else, so I trusted the seller when he assured me if I found anything Wrong with the truck, he would reimburse me and take the truck back.
Bought the truck for $7000.00 with 136,000 miles reading on the instrument panel, And brought it to a mechanic the next day for inspection. Turns out, the seller had rolled the odometer back from the 250,000 miles clocked on the truck last time it was registered (2022) , Had welded clogged catalytic converters that were the wrong cats for the truck, ripped out both downstream O2 sensors, and I suspect deactivated the check engine light somehow.

I have since purchased an exhaust manifold from the junkyard, which had quality parts from the same truck with 80,000 miles on it with both cats still attached to the system And installed them Along with OEM Denso oxygen sensors. Last thing I need to do now is fix this check engine lightbulb so I can get it smog and registered.

I can’t figure out what is wrong. I have taken the instrument panel off and depart and inspected the LED light that should be working when I turn on the vehicle, but it never lights up. What could possibly be the issue? I suspect this person disconnected it, intentionally to hide the many problems that were wrong with the truck when I bought it, but I don’t know how he would’ve done that.

Does anybody have any insight? Thank you so much for your help.

 

Some LED bulbs need correct polarity. Did you try turning the bulb 180 degrees in the holder? And really do you need the bulb to illuminate to get it smogged? Either you have codes or you don't. Have you had it hooked up to a OBD reader? That will point you in a direction of what you need to fix.

 

Thanks for the reply. I thought the CEL had to be functioning for it to pass smog but I suppose the codes are what they will look for. I thought they might notice the light not lighting up when it starts.

also, after disassembling the instrument panel, there were no bulbs to replace, just a motherboard with tiny led lights soldered in place, none looked burnt out on visual inspection

 

You will need the dashight to pass smog testing, but we are more concerned with what codes that are present. There will be codes.

 

Yes there are, or there were until I fixed as many as I could as listed in my original post. Let me find the file that I have from the mechanic …

 

The truck must be in limp mode with those air pump codes in place.

Besides that, I think you have a case for fraud and can demand your money back. Those are some serious codes and they will definitely trip the CEL.

 

I am aware I have a case for fraud but the guys Armenian and from what I could see on his Facebook profile ( I’m blocked now) he and his dad do this for a living. I posted a warning post about him and in under an hour there were 4 different ppl reaching out to me saying they also got burned by the guy.
I’d take him to court but he won’t show up , I’ll win and then he will never pay me. Plus all of that will likely take years. I just spent all of my money on this truck as I need it for work and am trying to get it fixed as best as I can . So far I’m in over $9,250.00 and I don’t have anything left to be able to eat the bill while I wait for the court to process

 

What do you mean by limp mode? I disconnected the neg terminal and am going to have auto zone scan it again in a few minutes to see what the new cats and o2 sensors managed to fix. Hopefully most of them

 

The air pump codes will put the truck into limp mode. You won't be able to go much faster than 45 mph.

When you disconnect the battery, it may clear them temporarily, but they will come back and force you to drive slow.

 

Actually it must not be in limp mode then because I have no problem going over 70 when I do drive it

 

How long do you think I have to drive it before the codes pop back up do you think? I’m hoping the catalytic repair and new 02 sensors will keep at least most of them from coming back on tho,…

 

Good to hear. I wonder if the previous owner bypassed the AIP system.

I wish I could offer more help, but I think you are not gonna have a good outcome.

Best of luck.

 

Aww man don’t say that without context! What makes you think this truck is not repairable?

 

Any update based on the new info ?

 

This was my thought also.

I doubt there was a cat issue. Bet it was O2 but beside that it’s an interesting array of codes.

He’s in it for at least SAIP and its valves. No big deal. But the cluster of codes makes me think there’s something more going on. Any evidence of harness hacking? or replacement of harness, like maybe the grommets at the firewall are missing or cut?

If this is the state of the engine I wonder about the state of the frame?

And yeah, the LED is soldered to the board. I bet they cut a trace to make it not light up. Shady fucks.

You know if you don’t raise a case against them, these guys will do it again. I’d you have four others you may want to file a criminal case, or a combined civil case. If nothing else, contact your state’s consumer protection division. Else these bastards will keep victimizing people.

 

I know that your priority is getting your truck fixed but the seller needs to stop taking advantage of people. You also need to try and recover some of your repair costs back. I am assuming this person is not an official “dealer”. Most states have laws that classify a person as a dealer if they sell a set number of vehicles (3-5) per year. If the seller is selling cars that are not titled in their name there are also sales tax implications. Most states take sales tax evasion very seriously. Not saying that’s what the seller is doing but if he is I would contact the state.

I would document the problems with the truck and take it to small claims court. It would be best to have an estimate from an independent shop. Even if you think he will not pay, I would make an effort to get a judgement.

 

Rolling back an odometer is a felony and it will end up with the secretary of states office. I dont think he will run away from the law for long once they get a case built against him.

 

Agreed. As far as the odometer issue, it dawned on me that it’s possible he replaces the instrument panel with a different one, and could be the possible explanation for the discrepancy for the mileage? That would make sense but I’m not sure if they work that way. Also I’m not certain I understand if the panel would be stock or not as it looks exactly like the diagram from the manual , but when I go to replace the check Engine Lightbulb (aka Malfunction Indicator Lamp) I find it is not a lamp but is instead leds on a circuit board. Does that mean it’s aftermarket or am I misunderstanding something important?

I afeee with you though, I need to put some pressure on him legally or he will continue to do this to people. I’m not even sure how to do that though. Just show I’m up at the courthouse and show them his Facebook (likely a nickname but real pics of him) profile and say “hey here’s the high o want to sue. I’m not sure what his name is or even if he’s in the country legally, but here’s pics of him . Let’s get him!”

I feel like I’d need to hire a Private Investigator just to pursue this at all and I’m so flat broke with fixing things on the truck that I don’t even have my half of rent this month still…I’m trying to. Not let it all boil over and get the advantage on me but it’s hard so I’m trying to focus on what I can control as of now.


Really just want the fucking check engine light to work so I can smoke now . Please help me understand

 

I think he replaced the instrument panel at some point but am not sure. How do I bring their awareness to him without knowing his name though?

 

??? no clue

 

Can I take some pics in the areas you want to get a look at so you can tell me what you think?

Also it definitely was having problems from the cats. they were originally for/to a completely different, much smaller vehicle and heated up waaay too much/were clogged and preventing airflow. The ones I replaced them with combined with new downstream sensors has given me the power I was missing when punching it on the freeway going 50 already, only to find it not push forward much more than that. Still would get up to 70, but took waaaay too long. Now the powers available but it still sounds like a lawnmower kinda. Tech guy thinks it’s almost for sure a leak in the exhaust system. But I can’t be sure.

I’m Trying to figure out the next step besides the check engine light. Think I’m gonna swap the upstream sensors as well since one was pulling a code, but I’m not sure if that’s from the downstream ones not being installed at all or what the issue was . But now that I’ve got four installed, I’ve reset the computer and am taking it thru its drive cycles, will update tomorrow what codes I get this time.

Big thanks to all for your help and for any advice you might have , I really appreciate it!

 

Op, if you have multiple people that have been screwed over by the guy, contact the dmv, state attorney generals office, and state tax department.

 

2005-2006 clusters were all on-board LED. This is why I’m suspecting he cut a trace on the circuit board of the cluster to disable the check engine LED. Swapping in a cluster from another 2005-2006 would unravel whether he tampered with the circuit board or not. If he didn’t, I’d need to dig thru the wiring diagrams for our truck to see if there’s another wire or circuit he maybe disconnected or cut.

 

Everyone here is cool with helping on pics.

Exhaust leaks are common in northern trucks, and exhaust manifold cracks (and broken studs) are also commmon in these trucks overall.

For other stuff, if you don’t already have one of each, hit the auto parts store. Get a can of MAF cleaner, and a can of Throttle Body cleaner. I prefer CRC brand.

This is something you can easily do at home. I am happy to give advice on cleaning both the MAF and TB (I can link some videos) if you’d like. It’s worth doing now just to have a baseline. You should remove the negative battery cable for 10 minutes after cleaning to force the ECU to learn and adapt to the new, cleaner intake and airflow.