P2443: Secondary air injection switching valve stuck closed, bank 2

Secondary air injection switching valve stuck closed (bank 2)

Severity: Severity not verified — if the car runs badly, have it inspected

Owner complaints describe a check engine light that can come with reduced power (limp mode) and a failed emissions test, but no maker document read for this page rates the risk.

It gets more serious if:

Inspect soon: Get it inspected soon if the truck loses power or goes into limp mode, as two owners of Toyota trucks reported.

Source: how we rate severity

P2443 in short

P2443 means the computer found the bank 2 secondary air injection switching valve stuck closed, so the extra air it pushes into the exhaust at cold start is not getting through. Owner reports on Toyota trucks point to the air pump or valve. It can cause limp mode and a failed emissions test.

Secondary air injection blows fresh air into the exhaust for the first minute after a cold start so the catalyst warms up faster and burns off extra emissions. A switching valve opens and closes the air path to each side of the engine.

P2443 is set when the computer tests the bank 2 side and finds the valve behaving as if it is stuck closed. The valve, the air pump that feeds it, or the pump relay and wiring can all produce that result, so the code alone does not say which part to replace.

Several Toyota Tundra and Tacoma owners report limp mode with this code, and a Subaru owner failed a smog test with it. One Toyota owner had the pump replaced twice and the code returned.

Most likely causes

Cause 1: Bank 2 secondary air switching valve stuck closed
Supported by vehicle data
Why it ranks here
The code names this valve. Toyota owners report P2443 with a dealer quote for a valve or two pumps.
What would change this
Raises if the scan tool commands the system on and no air reaches the bank 2 side; lowers if the valve moves freely and the pump runs.
How to test the secondary air pump
Cause 2: Failed secondary air pump
Supported by vehicle data
Why it ranks here
A Toyota dealer quoted pump replacement and another owner had the pump replaced with the code returning, so the pump is part of the repair even when the valve is named.
What would change this
Raises if the pump does not run or moves little air when commanded; lowers if it runs and the valve still does not open.
How to test the secondary air pump
Cause 3: Relay or wiring in the secondary air circuit
Possible — needs testing
Why it ranks here
One Subaru owner links the code to a recall for a relay in the secondary air circuit. The recall text was not read, so this stays a thing to test.
What would change this
Raises if the relay or fuse is open or the pump has no power when commanded.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Read all stored codes. Note whether other secondary air codes such as P2441 or P2440 are stored, and whether the engine has gone into limp mode.
Low riskTool: OBD-II scan tool
- IfOther secondary air codes are stored for bank 1 or the pump
  It meansThe pump, relay or a shared supply is more likely than one valve.
  Go to step 2
- IfOnly P2443 is stored
  It meansThe bank 2 valve or its air path is the first suspect.
  Go to step 2
Step 2: Ask a dealer whether your VIN has an open recall or warranty extension for the secondary air system.
Low risk
- IfA recall or warranty applies
  It meansHave the covered repair done first.
  Points to: Relay or wiring in the secondary air circuit
- IfNothing applies
  It meansTest the system with the scan tool.
  Go to step 3
Step 3: With a scan tool that supports it, command the secondary air system on and check that the pump runs and air reaches the bank 2 valve; test the relay, fuse and pump supply voltage.
Best left to a shopTool: scan tool with active tests, multimeter
Warning:The pump draws high current and the air hoses and exhaust parts near the valve get very hot; do not touch them after the engine runs.
- IfThe pump runs but no air gets through the bank 2 valve
  It meansThe switching valve is stuck closed.
  Points to: Bank 2 secondary air switching valve stuck closed
- IfThe pump does not run or is weak
  It meansTest its power and relay, then suspect the pump.
  Points to: Failed secondary air pump

Symptoms

Check engine light, sometimes with the traction control light, at start-up
Reduced power or limp mode Gets more serious: stop and have it checked.
Failed emissions test

How to fix

Parts and cost context

Secondary air pump:A Toyota dealer quoted a repair covering two pumps or a switching valve, so ask which parts the diagnosis calls for. Labor varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Toyota

2008 · Tundra
Supported by vehicle data
Owner complaint 839863 reports P2443 and limp mode on a 2008 Tundra, with a dealer quote for two pumps or a switching valve. No bulletin was found in the local cache.
2012–2014 · Tacoma
Supported by vehicle data
Several Tacoma owners report P2443, reduced power and a repeat failure after a new pump (complaints 1430842, 1437992, 2030182). No bulletin was found in the local cache.

Subaru

2010 · Forester
Supported by vehicle data
A 2010 Forester owner reports P2441 with P2443 and a failed smog check, and links it to recall 16V-738 (owner statement; recall text not read).

All Secondary air injection codes

P2443 questions

Can I drive with P2443?

Usually, but some Toyota owners report limp mode with reduced power, which is unsafe in traffic. Get it checked soon and do not expect to pass an emissions test with the light on.

Is the air pump or the valve at fault?

The code does not say. The pump, the valve and the relay can all cause it, so test them with the scan tool before replacing parts.

Sources and review

NHTSA complaint ODI 839863: 2008 Toyota Tundra, P2443 and limp mode — NHTSA (owner complaint)
NHTSA complaint ODI 1430842: 2012 Toyota Tacoma, P2443 with TRAC and check engine lights — NHTSA (owner complaint)
P2443 Trouble Code Explanation — TroubleCodes.net
NHTSA complaint ODI 1437992: 2012 Toyota Tacoma, P2443 found by a mechanic — NHTSA (owner complaint)
NHTSA complaint ODI 2030182: 2014 Toyota Tacoma, P2443 returns after a new air pump — NHTSA (owner complaint)
NHTSA complaint ODI 1346017: 2010 Subaru Forester, P2441 and P2443 and a smog failure — NHTSA (owner complaint)

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Severity not verified — if the car runs badly, have it inspected

Most likely causes

Cause 1: Bank 2 secondary air switching valve stuck closed

Cause 2: Failed secondary air pump

Cause 3: Relay or wiring in the secondary air circuit

What to test first

Step 1: Read all stored codes. Note whether other secondary air codes such as P2441 or P2440 are stored, and whether the engine has gone into limp mode.

Step 2: Ask a dealer whether your VIN has an open recall or warranty extension for the secondary air system.

Step 3: With a scan tool that supports it, command the secondary air system on and check that the pump runs and air reaches the bank 2 valve; test the relay, fuse and pump supply voltage.