Limp Mode with permanent error codes

About three weeks ago my 2016 taco went into limp mode. My mechanic took a look at and ran a scan. He said it was the secondary air injection pump that was causing the issue so we got a new one and installed it.

I got the car back but it’s still in limp mode so my mechanic didn’t charge me for service just the part. I got my own OBD scanner and ran it and it gave 4 permanent dtc codes, all having to do with the secondary air system. From doing some reading, I understand that I gotta do a couple drive cycles in order to show the ecu that the parts are new and working.

How the hell am I supposed to complete a drive cycle if it’s in limp mode?

I took a pic of the error codes, P0412 just popped up new because i tried plugging and unplugging the valve. If anybody has any advice, please help

 

Get a new mechanic

 

What was all the talk here on TW earlier this week about touching the battery cables together for five minutes or so, maybe 15 minutes to reset the ECU?
Cables are OFF of the battery of course.

Will an ECU reset clear these codes? It will clear everything else it has learned (shift points, fuel economy, etc.).

Have you tried that OP?

 

Yeah, I reset my ecu and it cleared everything but the permanent codes and the check engine light stayed.

I think it’s time for a new mechanic, I just wanted to see if the internet could help before I poured any more money into this.

 

With them all bring circuit codes I'd be under the hood looking for chewed wires before putting any other parts on it.

 

@Bishop84

 

4 cyl or 6 cyl?

 

The switching valve is stuck and the truck is trying to prevent major damage.

Basically engine exhaust is being routed at your injection pump with nothing to stop it.


You need air injection valve likely.

Edit.......

Alright, so the easiest way to diag if its sticking open, take off the hose from the pump that leads to the valve.

If you can feel or hear exhaust, its stuck open, the valve failed.

It's rare that the driver cause the valve to open, they naturally fail closed, when they fail open its usually due to corrosion over time.

 

thank you for your willingness to help and contributions to this site. you are a class act.

 

For awareness, the permanent codes can only be cleared by the ECU. Once the issue is fixed the ECU monitors with pre-established criteria for that particular code, if met the code is dropped.

 

Sorry, I forgot to mention that we also got a new valve as well as the pump. I went ahead and checked if it failed just incase by feeling for exhaust but there was nothing coming out. This was after a cold start. Also 4 cyl.

Thanks you for responding, though. My bad for forgetting to say that.

 

I had a problem with chewed wires that I already got fixed but it’s possible that it could’ve happened again so I will check for that. Thanks for the response.

 

New doesnt mean good, were they aftermarket valves?

That code only typically triggers when they are letting pressure past them.

Good that you checked for pressure though, seems odd. Hard to diagnose.

 

No, they were brand new from toyota. I don’t need to get it inspected any time soon so my only goal is to get this out of limp mode so I can start taking it to work again.

 

How many miles on the truck and spark plugs?

 

240k miles on the truck and I got the plugs replaced at around 100k miles so they have about 130-140k.

 

Let’s start with new plugs