P2446 — Secondary Air Injection System Pump Stuck On #

Note: The description of code P2446 may vary depending on the vehicle manufacturer.

• Toyota/Lexus: Secondary Air Injection System Pump Stuck On
• GM/Chevrolet: Secondary Air Injection Pump Relay Stuck On
• Volkswagen/Audi: Secondary Air Injection System Pump On Too Long
• Ford: Secondary Air Injection Pump Control Circuit Stuck On

Summary for code P2446 #

The P2446 code indicates that the Secondary Air Injection System Pump—a device responsible for pumping fresh air into the exhaust system during cold starts to reduce emissions—has remained in the “on” position longer than the powertrain control module (PCM) expects. This is usually detected via the air pump relay control circuit, which is monitored by the engine computer. When this system doesn’t turn off as commanded, the PCM triggers P2446 to alert the driver or technician of a potential malfunction. This code is most commonly found in vehicles equipped with emissions control strategies that require a secondary air injection system. Although this issue rarely leads to immediate drivability problems, it can prevent your vehicle from passing an emissions test and could eventually cause further component damage if ignored.

Frequent symptoms for code P2446 #

When the P2446 code is set, symptoms may be subtle at first, especially because the secondary air injection system operates primarily during cold engine starts. However, some drivers or technicians may notice:

• Illuminated Check Engine Light (CEL or MIL)
• Failed emissions test
• Audible continuous operation of the air pump, even after the engine warms up
• Increased exhaust noise on cold start
• Possible decrease in fuel economy (rare)

Likely causes for code P2446 #

The causes for the P2446 code can range from simple electrical issues to more complex mechanical failures. Based on technician experience and OEM service bulletins, the most common causes are:

1. Faulty secondary air injection pump relay
2. Stuck or faulty secondary air injection pump
3. Wiring issues such as shorts to power or ground in the pump control circuit
4. Faulty PCM (Powertrain Control Module) (rare)
5. Corroded or damaged connectors at the pump or relay

Step-by-step diagnostic guide for code P2446 #

Accurate diagnosis is the cornerstone of an effective repair. Here’s how a master technician or an advanced DIYer should approach a P2446 code:

1. Verify the code with a reliable scan tool. Check for any other related DTCs that may provide more context.
2. Visually inspect the secondary air injection pump, relay, and associated wiring for obvious signs of damage, corrosion, or disconnection.
3. Listen for the pump—it should not run continuously after engine warm-up. If it does, suspect a stuck relay or control issue.
4. Test the relay by removing it and checking for continuity between terminals. Relays stuck in the closed position will show continuity where there should be none with no power applied.
5. Check the air pump control circuit for voltage with the engine off and on. Unwanted voltage with the engine off may indicate a shorted relay or wiring fault.
6. Command the air pump on and off with a scan tool (bi-directional control) if available, and observe actual operation.
7. Consult OEM wiring diagrams for your specific model to trace the circuit and pinpoint faults.
8. If all else checks out, consider PCM faults only after eliminating all external causes.

Possible repairs for code P2446 #

The right repair will depend on the underlying cause. Once the root of the issue is identified, one or more of the following actions may be necessary:

• Replace the secondary air injection pump relay if found stuck or defective
• Replace or repair wiring in the air pump circuit if shorts, opens, or corrosion are found
• Replace the secondary air injection pump if it is confirmed to be internally shorted or stuck
• Clean or replace connectors at the pump or relay if oxidized or loose
• Reprogram or replace the PCM (very rare; only after all other avenues are exhausted)

Can I drive with code P2446? #

In most cases, you can continue to drive with a P2446 code, but it is not recommended for long periods. The secondary air injection system is an emissions control device, so a stuck-on pump won’t usually cause immediate engine damage or drivability issues. However, prolonged operation may cause the pump to overheat, drain your battery, or lead to additional electrical problems. Additionally, you will not pass an emissions or state inspection with this code present, and ignoring it could result in more expensive repairs down the line. Address the issue promptly to avoid complications.

Vehicles most affected by code P2446 #

This code is most frequently encountered on vehicles where the OEM uses an electric secondary air injection pump controlled by a relay and monitored by the PCM. The following brands and models are commonly reported with P2446:

• Toyota/Lexus (especially 4Runner, Tundra, Sequoia, Tacoma, GS/LS series)
• Volkswagen/Audi (certain Passat, Jetta, A4, A6 models)
• General Motors (Chevrolet Silverado, Trailblazer, Colorado, GMC Sierra)
• Ford (F-150, Explorer, Mustang with certain V8 engines)

Common mistakes & best practices for code P2446 #

When troubleshooting or repairing a P2446 code, it’s easy to fall into some common traps. Here’s how to avoid them:

• Replacing the air pump without checking the relay or wiring—often, the relay is at fault, not the pump itself.
• Overlooking simple wiring issues such as corroded connectors or chafed wires.
• Failing to clear the code and retest after repairs—always verify that the repair was successful.
• Neglecting to check for related codes that might provide more diagnostic clues.
• Not consulting OEM service information—each manufacturer may have unique diagnostic procedures or updated parts.

FAQ express for code P2446 #

Here are answers to some of the most common questions vehicle owners and technicians have about P2446:

• Q: Can I clear the code and ignore it if my car seems fine?
  A: Clearing the code without fixing the cause will likely result in the code returning. While your car may drive normally, you risk failing emissions tests and causing further component damage.
• Q: How much does it typically cost to repair a P2446 code?
  A: Costs vary widely: replacing a relay is inexpensive (often under $50), but replacing the air pump or repairing wiring can run several hundred dollars. Dealer diagnostics and labor can add to the bill, especially on luxury vehicles.