OBD-II Code P2431: Secondary Air Injection System Air Flow/Pressure Sensor Performance

What Does P2431 Mean?

P2431 means the Powertrain Control Module (PCM) detects an illogical pressure reading from the Secondary Air Injection (SAI) system's bank 1 sensor. The SAI pumps fresh air into the exhaust during cold starts to burn unburned fuel and heat the catalytic converter. The code triggers when the sensor's pressure reading contradicts the system's commanded state.

Technical definition: The official SAE/OBD-II definition is "Secondary Air Injection System Air Flow/Pressure Sensor Circuit Range/Performance Bank 1". The PCM detects a voltage signal from the air pressure sensor that is irrational compared to the commanded state. For example, the PCM commands the air pump on and expects a pressure increase, but the sensor reports no change.

Can I Drive With P2431?

⚠️Yes, But With Caution. You can drive temporarily, but do not ignore it. Initial symptoms are minor, but ignoring the code causes the catalytic converter to overheat and fail, an $800 to $2,500 repair. Fix it within a month to avoid failing emissions and destroying the converter.

Common Causes

• Faulty or stuck-open one-way check valve (Very Common) — The check valve prevents hot exhaust gases from flowing back into the air pump. It frequently sticks open, allowing corrosive exhaust to contaminate the pressure sensor and flood the pump with water, causing total system failure.
• Failed secondary air injection pump (Very Common) — Moisture intrusion from a failed check valve destroys the electric pump motor. Water rusts and seizes the internal bearings, which blows the system's high-amperage fuse.
• Failed or stuck air pump relay (Common) — Common on Subaru models, the relay powering the air pump sticks in the 'on' position. The pump runs continuously past its 120-second duty cycle, overheating and creating a fire risk.
• Failed secondary air pressure sensor (Common) — Moisture and carbon soot bypassing a failed check valve damage the sensor, causing inaccurate voltage readings that trigger P2431.
• Clogged or restricted air passages/ports (Less Common) — Carbon deposits completely block the small air passages in the cylinder head or exhaust manifold. The pressure sensor detects no flow change even with a working pump. This is a known issue on Audi 2.0T engines.
• Damaged wiring or corroded connectors (Less Common) — Road salt corrodes the wiring harness or connectors for the pump, sensor, or solenoid. On GM vehicles, wires break inside the insulation near the MAP sensor, triggering a false P2431.
• Stuck or faulty air control solenoid/valve (Less Common) — Carbon buildup or mechanical failure sticks the switching valve open or closed, preventing commanded airflow.
• Faulty Powertrain Control Module (PCM) (Very Rare) — Internal circuit failure or corrupted software prevents the PCM from sending the 5-volt reference signal. Consider this only after ruling out all other hardware.

Symptoms

• Loud whining or vacuum cleaner noise on cold starts — A failing air pump makes a loud whirring or howling sound for the first 30-90 seconds after a cold start. It sounds like a hair dryer under the hood.
• Hesitation, rough idle, or stalling after a cold start — The engine runs poorly for the first minute after a cold start because the malfunctioning air injection system throws off the computer's fuel calculations.
• Decreased fuel economy — Inaccurate data from the SAI system forces the PCM to adjust the air-fuel mixture improperly, increasing fuel consumption by 5-10%.
• Check Engine Light is on (also visible on scanner) — The PCM logs the P2431 fault after a system self-test fails, illuminating the MIL.
• Failed emissions test (also visible on scanner) — A P2431 code illuminates the check engine light, resulting in an automatic failure of state-mandated smog checks.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this code.

Common Fixes & Costs

• Replace the secondary air injection pump and check valve(s) together — Parts: $250-$800, Labor: $150-$450, ~2.5 hr book time (Intermediate)
• Replace the air pump relay — Parts: $15-$50, Labor: $25-$75, ~0.5 hr book time (Beginner)
• Replace the air pressure sensor — Parts: $100-$250, Labor: $75-$175, ~0.7 hr book time (Intermediate)
• Replace the one-way check valve(s) only — Parts: $50-$400, Labor: $100-$250, ~1.5 hr book time (Intermediate)
• Repair or clean clogged secondary air ports — Parts: $20-$50, Labor: $400-$800, ~6 hr book time (Professional)

Used vs. New Parts: Buying Guide

When a used part is worth it: Buy a used air pump assembly from a low-mileage, rear-ended donor vehicle to save money on high-mileage cars. Avoid parts from vehicles scrapped for unknown or front-end damage reasons.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

Donor quality checklist:

• Verify the donor vehicle's mileage and reason for salvage.
• Inspect electrical connectors for corrosion and plastic housings for cracks or melting.
• Match the part number exactly; internal components differ despite visual similarity.

Decision logic:

• If Part is a simple relay or fuse → Buy new; the cost savings for a used part are negligible and not worth the risk.
• If Vehicle is over 150,000 miles and the new part costs over $500 → A used part from a reputable salvage yard with a warranty is an acceptable budget repair.
• If Part fails from internal wear or contamination (e.g., pump, check valve) → Buy new OEM or high-quality aftermarket parts. Used parts hide internal moisture damage.

Warranty tradeoff: Used parts offer a 30-90 day functional warranty. New aftermarket parts include a 1-3 year warranty. New OEM parts carry a 1-year/12,000-mile warranty.

Worst-case if a used part fails: $300-$800 if a used pump or valve fails prematurely, requiring repeat labor and a second replacement part.

What Happens If You Wait — Timeline

1. 0-1 month: Code sets and Check Engine Light illuminates. On Toyota models, VSC/TRAC lights also come on. The only symptom is a brief, loud noise on cold start. Emissions test is an automatic fail. (MPG impact: 0-5%% · Added cost: $0)
2. 1-3 months: Driver notices rough idling or hesitation for the first minute after a cold start. Fuel economy drops. If the cause is a stuck relay, the pump burns out completely. (MPG impact: 5-10%% · Added cost: $50-$150 in wasted fuel and potential cost of a new air pump ($250-$800) if the relay fails.)
3. 3-9 months: The catalytic converter consistently runs too rich and hot during the engine's warm-up phase. The internal ceramic substrate degrades and cracks from thermal stress. Engine performance feels sluggish. (MPG impact: 10-15%% · Added cost: $800-$2500 (catalytic converter replacement is now required).)
4. 9+ months: Complete catalytic converter meltdown. The substrate breaks apart and clogs the exhaust, leading to severe power loss and stalling. On Toyota/Lexus models, the ECU is destroyed. (MPG impact: 15-25%% · Added cost: $2000-$4000+ (includes catalytic converter, O2 sensors, and a new ECU).)

Cost of Not Fixing It

• 0-1 month: Failed emissions test, rough cold-start idle, and a 5-10% drop in fuel economy. (Added cost: Negligible, other than increased fuel cost.)
• 1-6 months: The catalytic converter operates outside its intended temperature range. The internal substrate overheats, melts, and clogs. (Added cost: $1200-$2800)
• 6+ months: A melted catalytic converter creates a severe exhaust restriction, causing major power loss, stalling, and engine damage. On Toyota V8s, a persistent fault destroys the Engine Control Unit (ECU). (Added cost: $2000-$4000+)

Diagnosis Steps

1. Read Fault Codes and Freeze Frame
   Use an OBD-II scanner to confirm P2431. Check for related codes (P0410, P0411, P2432, P2433). P2432/P2433 indicate electrical shorts, while P0411 suggests a flow blockage.
   Tools: OBD-II Scanner (Beginner)
2. Listen to the Air Pump
   Start the engine completely cold. Listen for the air pump to run for 30-90 seconds. Silence indicates a dead pump, blown fuse, or bad relay. A loud grinding noise means the pump is failing.
   Tools: None (Beginner)
3. Test the One-Way Check Valve
   Disconnect the large hose running from the air pump to the check valve. Inspect the hose and valve inlet for moisture or black soot. If present, the valve failed and destroyed the pump.
   Tools: Pliers or screwdriver (Intermediate)
4. Check the Fuse and Relay
   Locate the SAI pump fuse and relay in the fuse box. A blown fuse confirms a seized pump motor. Swap the relay with an identical non-critical relay (like the horn) to test if the pump turns on.
   Tools: Owner's Manual, Fuse Puller (Intermediate)
5. Inspect Hoses and Wiring
   Visually inspect rubber hoses for cracks and electrical connectors for green corrosion or melting.
   Tools: Flashlight (Beginner)
6. Test Sensor Response with Scan Tool (Pro Tip)
   Connect a bidirectional scan tool and view the SAI pressure sensor live data. Command the air pump 'on' with the engine running. The pressure reading must rise 8-10 kPa. If the value ignores the running pump, the sensor is faulty.
   Tools: Bidirectional Scan Tool (Advanced)
7. Verify Sensor Voltage (Pro Tip)
   Back-probe the pressure sensor connector with a multimeter (Key On, Engine Off). The reference wire must show 5V. The ground wire must show <0.1V. The signal wire must show 0.5V-1.0V. Readings of 0V or >4.5V indicate a short or failed sensor.
   Tools: Digital Multimeter, Wiring Diagram (Advanced)
8. Test the Air Pump Motor Directly
   Disconnect the pump's electrical connector. Supply 12V power and ground directly from the battery. If the pump fails to run, replace the assembly.
   Tools: Jumper wires or power probe (Advanced)
9. Manually Test Sensor with Pressure
   Attach a hand-held vacuum/pressure pump to the disconnected sensor. Apply 5-10 psi while monitoring voltage. Voltage must increase smoothly. Erratic jumps indicate a failed sensor.
   Tools: Hand-held Vacuum/Pressure Pump, Digital Multimeter (Advanced)

When This Code Triggers (Freeze-Frame Conditions)

• Engine Coolant Temp: 40-80°F (Cold start (engine off for 8+ hours))
• RPM: 700-1200 (Initial idle phase after cold start)
• Engine Run Time: 10-90 seconds (Immediately after starting the engine)
• Vehicle Speed: 0 mph (Stationary, during system self-test at startup)

Related Codes

• P0410 — P0410 is a general code for 'Secondary Air Injection System Malfunction.' It means the system failed its self-test, but doesn't specify why. P2431 is specific, telling you the PCM sees an illogical performance from the Bank 1 pressure sensor.
• P0411 — This code means 'Secondary Air Injection System Incorrect Flow Detected.' The PCM sets this code when it uses the oxygen sensors to verify airflow and sees no change. P2431 is based on the pressure sensor's direct reading.
• P2432 / P2433 — These are specific electrical fault codes for the sensor circuit. P2432 means 'Circuit Low' (short to ground or open wire), and P2433 means 'Circuit High' (short to power). P2431 means the sensor is electrically functional but sending an implausible signal.
• P0418 — This code points to a fault in the 'Secondary Air Injection System Relay 'A' Control Circuit'. It appears on Subaru models when the air pump relay fails and sticks, causing the pump to burn out.

Climate & Environmental Factors

• Cold Climates: Moisture from exhaust gas condenses in the system after shutdown. In freezing temperatures, this water turns to ice inside the pump or check valve. The ice seizes the pump motor when it attempts to run on the next cold start.
• High Humidity / Wet Climates: High humidity increases moisture condensation in the system. This water accelerates corrosion of the pump's internal bearings and electrical connections, leading to premature failure.
• Road Salt (Rust Belt Regions): Heavy road salt usage accelerates corrosion on the wiring and electrical connectors for the SAI pump and sensors, causing high resistance or open circuits.
• High Altitude: At higher altitudes, baseline atmospheric pressure is lower. A faulty barometric sensor affects the plausibility checks for the SAI pressure sensor, potentially contributing to a P2431 code.

How to Talk to a Mechanic About This Code

Say this: "I have a P2431 code and I'd like to schedule a diagnostic. I'd like you to check for moisture in the secondary air system, test the check valve, and verify the pump and sensor are functioning before recommending any part replacements."

This signals that you understand the common failure modes for this specific code. It directs the technician to perform a thorough diagnosis rather than just replacing the first part they suspect, saving you money on unnecessary repairs.

Avoid saying:

• 'My check engine light is on, can you look at it?' (This is too vague and invites a broad, potentially expensive diagnostic process).
• 'Just fix whatever is wrong.' (This gives the shop a blank check to replace parts without your approval).
• 'My friend said it's probably the sensor.' (This leads to confirmation bias, where the mechanic replaces the sensor without fully diagnosing the system).

Questions to ask before authorizing the repair:

• Did you find moisture or soot in the hoses or pump? (This confirms a failed check valve).
• Can you show me the failed part and explain why it needs to be replaced?
• If the pump needs replacement, are you also replacing the check valve and relay to prevent a repeat failure?
• What is the warranty on the parts and labor for this repair?

Where to Take It: Dealer vs Independent vs Chain

• Dealer:
  Best for: Vehicles under warranty (check for recalls or TSBs first)., Complex diagnostics on German brands like VW, Audi, or BMW with known quirks., When a specific Technical Service Bulletin (TSB) or software update is required.
  Downsides: Highest labor rates., May recommend replacing the entire system as a unit rather than individual failed components. (Typical cost: +50% vs. baseline)
• Independent Shop: Best overall fit for most out-of-warranty vehicles, provided you choose a reputable shop. P2431 is a common enough code that an experienced independent technician diagnoses it effectively.
  Best for: Out-of-warranty vehicles where cost is a factor., Common domestic and Japanese models (e.g., Toyota, Subaru, GM) where this is a well-known issue.
  Downsides: Quality and diagnostic capability vary widely. Look for shops with ASE-certified technicians and good reviews., May lack access to the latest manufacturer-specific software updates. (Typical cost: +0% vs. baseline)
• Chain Shop: AVOID for diagnosing P2431. The risk of misdiagnosis is high. They correctly identify a failed pump but miss the underlying cause (a bad check valve), leading to repeat repairs.
  Best for: Simple, high-volume jobs like oil changes, tires, and brakes.
  Downsides: Technician skill varies dramatically; lacks advanced diagnostic tools for complex electrical issues., High pressure to sell services leads to misdiagnosis and unnecessary part replacement. (Typical cost: -10% vs. baseline)

When to Walk Away From the Repair

If the estimated repair cost exceeds 50% of your car's private-party value, seriously consider replacing the vehicle instead of repairing it.

• Car worth $5000, fix is $2800: Walk away. The repair cost is over 50% of the car's value. It's not a sound financial decision.
• Car worth $15000, fix is $1500: Fix it. The repair cost is only 10% of the vehicle's value and well below the threshold.
• Car worth $3000, fix is $1500: Borderline. This is exactly 50%. Before authorizing, get a second opinion and consider the car's overall condition.

What Scan Tool You Need for This Code

Minimum: A scanner that reads live data for the Secondary Air Injection pressure sensor and commands the air pump on and off (bidirectional control).

A basic $20 code reader only shows the P2431 code. It cannot show live pressure sensor readings or test the pump, which are essential for diagnosis. You will guess at the cause and waste money replacing the wrong parts.

Budget: BlueDriver Pro Scan Tool (~$100) — Connects to your smartphone and graphs live data from the SAI pressure sensor. You see if the pressure changes when the pump runs. It provides freeze frame data and clears the code after repair.

Mid-range: Innova 5610 or Foxwell NT510 Elite (~$300) — These handheld scanners offer bidirectional control. This allows you to manually command the SAI pump to turn on. If you command it 'on' and hear it run, but the pressure sensor reading doesn't change, you isolate the problem effectively.

Professional: Autel MaxiCOM MK808 / XTOOL D8S (~$500-800) — Provides full bidirectional control, advanced live data graphing, and access to manufacturer-specific codes. These tools offer OEM-level diagnostics, helpful for complex issues on brands like VW or Audi requiring special procedures.

Rent vs buy: For a one-time diagnosis, auto parts stores lend basic scanners for free. However, these loaner tools cannot perform the bidirectional control needed for a proper P2431 diagnosis. If you plan to do your own repairs, investing in a 'mid-range' pick is highly recommended.

How to Clear the Code After You Fix It

1. Reconnect battery if disconnected for repair.
2. Use an OBD-II scan tool to erase the diagnostic trouble codes.
3. Perform the specific Secondary Air Injection drive cycle to confirm the repair.

Drive cycle (~20 minutes): Start the vehicle from a 'cold soak' (engine off for at least 8 hours). Let it idle for 5 minutes without touching the throttle. Follow with 15 minutes of mixed city/highway driving, including steady cruising between 45-60 mph.

Readiness monitors affected: Secondary Air System, Catalyst, O2 Sensor

Before emissions retest: drive at least 50 miles to fully set monitors.

Watch out for:

• Disconnecting the battery clears the code but resets all readiness monitors to 'Not Complete,' causing an automatic emissions test failure.
• The code returns within two drive cycles if you do not repair the root cause.

Will This Fail Emissions / State Inspection?

Yes — this code typically fails an OBD-II emissions inspection.

• California: An illuminated Check Engine Light from a P2431 code is an automatic failure. All OBD readiness monitors must be set to 'Ready' to pass.
• New York: The NYS DMV vehicle inspection includes an OBD-II scan. An active P2431 fault results in an immediate test failure.
• Texas: As of 2025, non-commercial safety inspections are no longer required, but an annual emissions test remains mandatory in 17 populous counties. P2431 causes an automatic failure.

Most Commonly Affected Vehicles

• Toyota Tundra (2005-2013) — Extremely common on 4.7L and 5.7L V8 engines due to moisture intrusion from failed check valves. Toyota issued warranty enhancement program ZLH. Driving with a failed sensor destroys the ECU.
• Toyota Sequoia (2008-2013) — Shares the same powertrain and SAI system as the Tundra and is equally prone to failure. Covered under warranty enhancement program ZLH.
• Subaru Forester (XT), Impreza (WRX/STi), Legacy (GT), Outback (XT) (2007-2014) — Failures are extremely common on turbo models due to a stuck air pump relay causing the pump to run continuously. This prompted safety recall WTM-73 due to fire risk.
• Volkswagen Jetta, Golf, Passat, Beetle (2005-2012) — Common on models with the 2.5L engine. TSB 26 19 02 notes pressure sensor contamination. A service kit (P/N 07K 198 125) with an updated sensor and adapter harness fixes the issue.
• BMW 3-Series (E90), X3, X5 (2006-2013) — Issues with the SAI system are a frequent complaint. Failures typically involve the pump, check valve, or clogged ports.
• Lexus GX 460, LX 570 (2010-2013) — Shares a similar system design with Toyota V8s and is prone to moisture-related failures. Lexus issued a warranty enhancement for this issue.
• Audi A4, Q5 (2.0T) (2009-2016) — Often presents with multiple circuit codes. A known issue involves carbon buildup blocking the secondary air ports in the cylinder head, requiring a specialized cleaning procedure (TSB 01 18 93).
• Chevrolet Trailblazer, Colorado (2004-2012) — TSB #PIP4409F notes that P2431 is falsely triggered by broken wires in the MAP sensor harness. Inspect wiring before replacing AIR components. The pressure sensor is integrated into the check valve assembly.

Manufacturer-Specific Notes

• Toyota/Lexus: The failure is so common on V8 models that Toyota issued Warranty Enhancement Program ZLH extending coverage to 10 years or 150,000 miles. Always check with a dealer first. Driving for an extended time with a failed sensor destroys the ECU.
• Subaru: A failed air pump relay is a primary cause of failure on turbo models. Subaru issued safety recall WTM-73 because the relay sticks, causing the pump to run continuously and create a fire risk.
• Volkswagen/Audi: For 2.5L engines, VW TSB 26 19 02 addresses sensor contamination and provides a service kit (P/N 07K 198 125) with an updated sensor. For 2.0T engines, Audi TSB 01 18 93 addresses clogged carbon ports in the cylinder head, requiring a labor-intensive cleaning procedure.
• General Motors (Chevrolet): On models like the Colorado and Trailblazer, TSB #PIP4409F warns that P2431 is set by broken wires in the MAP sensor harness, not a fault in the AIR system itself. A wiggle test on the MAP sensor wiring is a mandatory diagnostic step.

Real Owner Stories

2008 Subaru WRX with ~100k miles

Check Engine Light came on. Heard a loud whirring/vacuum cleaner noise that wouldn't turn off, even with the key out of the ignition. Smelled burning plastic.

What they tried:

1. Disconnected the battery to stop the noise and smell.
2. Searched online forums and found this is a classic symptom of a stuck secondary air pump relay.

Outcome: Replaced the faulty relay in the under-hood fuse box. The original pump remained functional despite overheating. Total cost was under $50. The fix was immediate and the code did not return.

Lesson: On turbo Subarus, if the air pump runs continuously, the relay is the culprit. This is a known fire risk covered by recall WTM-73; check with a dealer first.

2007 Toyota Tundra 5.7L V8 with 155k miles

Check Engine Light and VSC/TRAC lights came on. The truck went into 'limp mode' with reduced power. Loud vacuum cleaner noise on cold starts.

What they tried:

1. A local shop quoted $2,500 to replace the air pumps and valves with OEM parts.
2. Owner found Toyota had a warranty enhancement (ZLH), but their vehicle was outside the mileage limit.
3. Opted for a Hewitt-Tech bypass kit for around $400.

Outcome: Installed the bypass kit, which electronically mimics the signals of a working SAI system. This cleared the codes and took the truck out of limp mode. The physical pump and valves were left in place but inactive.

Lesson: For high-mileage Toyota V8s, an aftermarket bypass kit is a cost-effective alternative to OEM repair. However, these kits are for off-road use and fail visual emissions inspections in some states.

2006 Chevy Trailblazer 4.2L

Check Engine Light with code P2431. The engine attempted to stall on cold starts.

What they tried:

1. Replaced the air check valve first, but the code returned.
2. Replaced the air pump relay, but the pump and solenoid were confirmed working.
3. A forum search pointed towards a GM Technical Service Bulletin (TSB) about wiring issues.

Outcome: Following the TSB, they inspected the wiring harness near the MAP sensor and found a broken wire inside the insulation. Repairing the broken wire solved the problem permanently.

Lesson: On GM vehicles, P2431 triggers from a wiring fault in a seemingly unrelated sensor harness (like the MAP sensor). Always check for TSBs and perform wiring checks before replacing expensive components.

How to Prevent This Code From Triggering

• Periodically inspect the air pump inlet and check valve outlet hose for moisture (Every 15,000 miles or annually) — Catching a leaking check valve early by spotting moisture prevents it from flooding and destroying the expensive air pump.
• Clean electrical connectors and apply dielectric grease (Every 30,000 miles, especially in rust belt regions) — Prevents corrosion on the pump, sensor, and relay connectors, which causes high resistance and triggers performance codes.
• Ensure the engine air filter and housing are properly sealed (At every air filter change) — The SAI pump draws air from the clean side of the engine air filter housing. A cracked housing allows debris-laden air into the pump, causing premature wear.
• On high-risk vehicles (e.g., Subaru turbo models), proactively replace the air pump relay (Once every 60,000 miles) — The relay is inexpensive ($25-$50) and a known failure point that causes the pump to run continuously and burn out.

Frequently Asked Questions

What are common mistakes when diagnosing P2431?

A frequent mistake is replacing the pressure sensor without full diagnosis. The sensor accurately reports a problem elsewhere, like a dead pump or stuck valve. Always verify wiring, fuses, and check for moisture before replacing expensive parts.

My mechanic suggested an 'air pump delete' or 'bypass kit.' What is that?

Bypass kits electronically trick the ECU into thinking the SAI system functions perfectly, turning off the check engine light. However, these kits disable a required emissions control device. They are illegal for street use and cause automatic visual emissions inspection failures.

Can I just replace the fuse if it's blown?

No. A blown fuse is a symptom of a seized pump motor caused by water intrusion. Replacing the fuse without fixing the pump causes the new fuse to blow immediately.

Will this code cause my car to fail an emissions test?

Yes. The secondary air injection system is a critical emissions component. An active P2431 code causes an automatic failure of any state emissions inspection.

Why does this problem happen so often in cold or wet climates?

The system is highly vulnerable to moisture condensation from exhaust gases. If the check valve fails, water enters the pump and freezes in cold weather. This ice seizes the pump motor when it attempts a cold start.

Will the P2431 code clear itself?

No. P2431 is a hard code indicating a persistent hardware or performance failure. The Check Engine Light remains on until you repair the underlying fault and clear the code with a scanner.

Why did my VSC/TRAC light also come on with the Check Engine Light?

Toyota and Lexus automatically disable vehicle stability control (VSC) and traction control (TRAC) when detecting a powertrain fault. This is a built-in safety precaution. Fixing the P2431 code and clearing the Check Engine Light restores VSC and TRAC functions.

Key Takeaways

• Inspect the secondary air injection check valve for moisture or carbon soot, as a stuck-open valve is the root cause of over 80% of P2431 failures.
• Listen for a loud, 60-to-90-second vacuum cleaner noise on cold starts to instantly identify a failing air pump motor.
• Replace the $50 air pump relay immediately on 2007-2014 Subaru turbo models if the pump runs continuously after shutting off the engine to prevent a vehicle fire.
• Fix a P2431 code within 30 days to prevent unburned fuel from melting the internal substrate of your catalytic converter, which turns a $300 repair into a $2,000 replacement.