Code P2443
 

Since changing the spark plugs last week, we are periodically getting Code P2443 OBD-II: Secondary Air Injection System Switching Valve (AISSV) Stuck Closed. I did have to redo a butt splice to a previous repair to the plug that goes onto the sensor next to the AISSV on the drivers side, but I’ve checked that several time and it is solidly connected as are the other 2 wires to that plug. When I pulled the AISSV to replace the spark plugs, I unplugged the harness and laid it up ontop of the intake.

This code only appears infrequently on start up. Per the description of its function, it pumps external air into the exhaust on cold starts. So I’ve checked wiring. Will check vacuum hose. Not sure how to check the rest.

P2443 OBD-II: Secondary Air Injection System Switching Valve Stuck Closed
Get diagnosis and repair information for trouble code P2443
OBD II Fault Code
OBD II P2443
OBD-II Code Powertrain Control Module (PCM) failure is defined as a Secondary Air Injection System Switching Valve Stuck Closed

The Secondary Air Injection System pumps outside fresh air into the Exhaust System during cold engine start up. This additional air helps burn up the highly rich exhaust emissions that are produced when the engine is warming up. The Secondary Air System typically has an Air Pump and some tubes or plumbing to route the air. The system also has a solenoid and Check Valve(s) to control the airflow. When the engine control module (PCM) detects a faulty with the Secondary Air Injection System, it will set code P2443.

Common Problems That Trigger the P2443 Code
Clogged or disconnected vacuum hose
Powertrain Control Module (PCM) failure
Secondary air pump control valve failure
Secondary air pump failure
Wiring issue

1. Get the official 4Runner repair manual: TOYOTA 2016-2019 4Runner Repair Manual RM27F0U

2. Run the procedure on page 3163 of the repair manual: " Inspect secondary air injection system operation".

3. You will find a diagram of the secondary air injection system on page 3591 of the repair manual.

4. Did you change the secondary air valve as the code indicates? (The repair manual calls it the "Air switching valve for secondary air injection". )

There are several other diagnostic tests in the repair manual that address the secondary air injection system.

Butt splice on a spark plug wire-did I get this right? I would never do that. I suggest replacing the whole wire with a new one. A spliced wire might be arching due to the high voltage.

No you did not read that right. It is a sensor next to the air valve. They sell replacement plugs for it, designed to be spliced in. Wire pulled out of the OEM plug and there is no way to get the wire back in. Over 140K miles on the truck since that repair.

Thank you for posting this. No on #4. We are currently driving from Montana to SoCal, laying over in Salt Lake City. I will do the repair manual tests when I get down to SoCal. Truck is running perfect and has not thrown a code, so it is definitely on cold start up and the temp was 50 F this am in Stevensville, but even then it is not consistent.

75 F this am in South Salt Lake City and no codes. Next stay is home in Fullerton, CA

I could not figure out that post with the manual. There is no link to download the manual, only a 7Zip file to unzip the download.

Update: Finally got the repair manual downloaded and opened.

Have not replaced the secondary air valve. Trying to confirm that the following is the correct part:

2014 Toyota 4Runner Valve assembly. Vacuum switching, no. 1; vacuum switching, no. 2 - 2586036020 | Tustin Toyota, Tustin CA

Got the secondary air valve from Toyota. Replacing it takes less than 5 minutes. Had not seen the code for at least 2 days before replacing. No code after starting it. Let it sit for 30 minutes and the code is back.

Toyota Manual is based on having Tech Stream, which I assume is Toyota's computer diagnostic system. Sounds like this will end up being a dealer repair if I can't resolve this.

Please keep us informed!

Alright, long week of work writing up quarterly deliverables on the bank I cover at the Fed Reserve. With the light of day on the weekend, I revisited the Secondary Air Valve. First thing, I pulled it to inspect the male side prongs of the plug on the valve and none were bent. So the electrical checked out fine. Did some other checks on the vacuum hoses and noted a rattle inside the valve, so I disassembled it by removing the 4 torx screws holding it together. When I split it open a piece of spring steel fell out. I think I found the problem. Pics attached. Also pic of butt splice repaired harness for the sensor (not the spark plug) under the Secondary Air Valve. New valve has been ordered at Toyota dealer and will arrive Tuesday. This will take just minutes to install.

I think that is a significant find!

Since replacement part is on order, decided to do a little further disassembly of the valve. The two philips head screws sheared off as they were mushroomed on the back side to prevent separation of that plate from the underlying grate. The entire plate/grate simply rests in a rubber gasket and in theory is replaceable. Honestly, probably could salvage this Denso made valve by purchasing a Valve by Dorman at 1/3 the cost and swapping in the plate/grate. I will be hanging onto this Denso made valve for that purpose.

Anyway, got the plate separated from the underlying grate and you can see where the spring steel flap sheared off from.

Nice investigation!
Could you see the back side of the screws before the heads sheared off or just didn’t notice ?

Valve isn’t cheap!

No could not see the back side of the screws….until the whole thing dumped out of the valve. Doh!

I could grab the back side ends of the screws with vice grips and remove them. But since the whole plate/grate unit just drops out, it would be pretty simple to swap in a new unit.

I definitely can find the valve cheaper for like $200 from On-line Toyota OEM Parts suppliers. But it’s my wife’s truck, so repairing sooner is better. I was tired of her coming to grab me to erase the code with the code reader.