2006 4cyl 4x4 181k new noise on start up

Hey TW peops! A few days ago I noticed that my Taco started making a new noise upon start up. While noises are a bit tough to describe, but here goes: it sounds like a vacuum line or similar has come loose, but goes away after it warms up. It's like a slight "gurgling" or "grumbling" sound. Nobody else would really notice the new noise, but since I've been driving it since new, I hear EVERY little vibration and squeak. There's also a somewhat slight tappet or other valve noise that just developed, too.

What's more, the check engine light popped on yesterday when I started it up after it sat for 3-4 hours. I was able to reset it when I got home (unhooked the battery for a while). It didn't come back on until this morning - which I assume is a cold-start problem. I am planning a visit to Advance Auto to get the code checked - so this post might be a little premature.

So my thoughts are: 1) bad gas - I mean the rough-ish idle and new valve noise hints at this; or 2) a vacuum line is unhooked or damaged - but I looked and looked and didn't see anything obvious.

Any other things I should be thinking? I don't suspect anything major since all the above noises are pretty minor (but new) and my oil, coolant, brake, power steering, etc. fluids are clean and topped-off.

Thanks y'all!

 

There's no code to read now that you've already reset it.

Sometimes there are pending codes, based on x keystarts that can be read, but not sure if Autozone's tool will do that or not.

 

Actually I wasn't clear. The code came back on upon start up this morning. I was able to reset it yesterday after work. So, I have a check engine light on right now which I'll get read at the parts store. Sorry about that.

 

I'll 'guess' at the code. O2 sensor, heater circuit. PURELY a guess. But hey, that's what internet diagnostics are for.

Of course that would have nothing to do with the running or noise issues.

Let us know what the code is.

 

So here are my codes (all relate to the same thing, in pretty sure):

P0418
P2441
P2445

Will do some research later unless one of y'all crazies has the exact diagnosis. Seems like last time this happened I got the same codes and it was a vacuum line that I forgot to reattach to the air box or something. I doubled checked and I don't see a line that's off. Ugh.

 

P0418 - Secondary Air Injection System Relay 'A' Circuit Malfunction

- Possible symptoms - Engine Light ON (or Service Engine Soon Warning Light) - Engine hesitation P0418 Description An air pump is used on the vehicle to lower tail pipe emissions on start-up. The Powertrain Control Module (PCM) grounds the Air pump relay control circuit which energizes the Air pump. The PCM also grounds the Air combination valve vacuum control solenoid circuit, which energizes the Air vacuum control solenoid. Vacuum is then applied to both Air combination valve diaphragms which opens the shut off valves. The PCM enables both circuits simultaneously when Air system operations id desired. When the AIR system is active, then Air pump forces fresh air into the exhaust stream in order to accelerate catalyst operation. The AIR combination valves replace the conventional check valves. When the AIR system is inactive the shut off valves prevent air flow in either direction.

P2441 - Secondary Air Injection System Switching Valve Stuck Closed

- P2441 Description To accelerate the activation of catalyst when warming up the engine, the air injection system pumps the secondary air to the exhaust manifold by pressure. The secondary air is supplied by the air pump and it is pumped to the exhaust manifold through the air switching valve. Open and close movement of the air switching valve is regulated by the Vacuum Switching Valve (VSV).The air pump and the air switching valve are observed by the Engine Control Module (ECM) and are used to detect malfunction in this system. The ECM monitors the secondary air injection system and detects malfunction using a pressure sensor located on the air switching valve. The ECM observes the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system. The sensor detects an exhaust pressure in the secondary air passage.

P2445 TOYOTA - Secondary Air Injection System Pump Stuck Off Bank 1

- P2445 Toyota Description To accelerate the activation of catalyst when warming up the engine, the air injection system pumps the secondary air to the exhaust manifold by pressure. The secondary air is supplied by the air pump and it is pumped to the exhaust manifold through the air switching valve. Open and close movement of the air switching valve is regulated by the Vacuum Switching Valve (VSV).The air pump and the air switching valve are observed by the Engine Control Module (ECM) and are used to detect malfunction in this system. The ECM monitors the secondary air injection system and detects malfunction using a pressure sensor located on the air switching valve. The ECM observes the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system. The sensor detects an exhaust pressure in the secondary air passage.


Found using this site: http://www.autocodes.com/p2445_toyota.html

 

Well, I finally decided to crack the hood and try to fix this annoying check engine light. First, like any good shade tree mechanic, I watched the YouTubes on the interwebs and found the process for disassembling the secondary air intake components. I next unbolted the secondary air intake pump, which came off really easily (its the park near the air cleaner box). I put it on the bench and disassembled it - again, fairly easily except for seized-up bolts. When the cover of the pump came off, I immediately noticed something odd. A few fins on the fan/impellor were damaged. There was an odd wad of brownish greasy mud-like substance jammed in the intake port on the pump. I was able to scrape it off and clean it with some carb cleaner. The broken fins don't seem to affect the pump motor operation.

Since there was this odd substance in the pump, I figured I should check the switching valve/solenoid (which is bolted to the exhaust manifold). I had to take off the exhaust pipe that runs from the switching valve to the exhaust manifold. The bolts were seized on even with some PB Blaster and penetrating oil. They eventually came off, but one freaking snapped the end of an exhaust stud. So, off to the parts store (Autozone actually had a M8 1,25 stud that worked in a pack of 2 for like $4). Now, getting the damn broken stud out of the exhaust manifold was a bitch. I eventually broke down and pulled out the MIG welder and spot welded a nut on the end of the broken stud so I could back it out. That work like a champ, but took some extra time. (be careful if you get the Autozone studs as the nuts are soft as s*** and the threads will ball up).

Okay, so back to the switching valve... I was able to separate the top from the bottom housing (small Phillips head screws were hard to get out and were pretty seized - luckily I got all three out without jacking up the heads). When I got it apart, I immediately saw another issue - there was a similar type material stuck in the solenoid gasket. It was like soft steel wool coated in grime. I'm at a loss as to where the hell this stuff came from, but obviously the air pump sucked something in along the way and shot it into the switching valve/solenoid. I cleaned all that stuff out and the solenoid valve was able to be moved (by gently putting a flat head screw driver under the gasket and prying it up and letting it pull back down). I cleaned the whole thing with carb cleaner and re-assembled.

Voila! No more check engine light! Hopefully it last.

Cautions:
1) Plan on your exhaust studs and associate nuts to be totally unusable when you take off the switching valve and exhaust tube. Preempt this by buying some at Toyota (they're cheap-ish) or an auto parts store.

2) Be patient - let the penetrating oil do it's job and soak all the seized nuts and bolts. I was not patient and it cost me a trip to Autozone at 8:30 at night and about a hour and a half time to fix my problem.

3) Try not to drop any nuts while doing said fix. I dropped one and it ended up winning the game of hide and seek by hiding in a frame hole. Sigh. Not a big deal, but pisses you off to have to search for 20 minutes to find a messed up nut. Oh, and my 12mm socket is still lost in there somewhere. If fell and never hit bottom. Just silently disappeared. Sigh again.