Fix P2433: Mechanic’s solutions that WORKED

The OBD2 code P2433 relates to the Secondary Air Injection System Pressure Sensor Circuit High. In simpler terms, this code indicates that the vehicle’s onboard computer has detected a signal from the secondary air pressure sensor that is higher than expected. This system is crucial for reducing emissions by introducing fresh air into the exhaust stream to aid in the more complete burning of exhaust gases.

P2433 quick overview

Meaning	P2433: Secondary Air Injection System Pressure Sensor Circuit High
Is it serious?	Yes, it can affect the vehicle’s emissions and, in some cases, its overall performance.
Possible causes	– Faulty secondary air injection pump – Clogged or leaking check valve – Damaged or corroded wiring connectors or relays – Incorrect hose installation – Water accumulation in the air pump
How to diagnose?	Inspect the secondary air injection system for any leaks or blockages. Check the integrity of electrical connections and the condition of wiring. Perform a smoke test to identify any leaks. Replace faulty components such as the air pump, check valve, or sensor. Consider a reflash of the ECM if the problem persists.

How to fix P2433 – learn from mechanics

I looked into P2433 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Volkswagen

Vehicle Information 2012 Volkswagen Passat SE 2.5L Map Sensor

Issue + Repair History

• Check engine light illuminated.
• Codes: P2433 and P2432 (short to negative and short to positive for secondary air pressure sensor).
• Replaced secondary air sensor as per manufacturer instructions.
• After replacement, code P2433 (short to negative) persists.

Other OBD2 Codes + Test Results

• 12v pin 1 to bat +: Has 12v
• 5v pin 3 to bat +: Has 5v
• 1.5 ohms pin 4 to pin t60/55 at ECM: Has 1.5ohms

Mechanic Suggestions

• Check voltage from the sensor at the PCM pin; should be less than 4.5V.
• Investigate the possibility of a broken wire or high resistance.
• Consider bulletin on sensors, which may require installing a new pipe with pigtail and pressure sensor.
• Look into updated sensor and hose combo from VW, ensuring the sensor comes attached to the hose.
• Inspect the system for any leaks.
• Suggests creating a jumper harness to the ECM temporarily to see if the code disappears; if successful, make it permanent.

Final Fix The final repair involved making a jumper harness to the ECM, which resolved the issue permanently.

Case #2: Chevrolet

Vehicle Information 2008 Chevrolet Trailblazer LT 4.2L

Issue + Repair History

• MIL (Malfunction Indicator Lamp) illuminated.
• Clean water observed in the air pump.
• Possible causes discussed include a stuck open or leaking check valve allowing exhaust condensation, leading to water accumulation in the air pump.
• Former owner traded in the vehicle rather than fixing the issue.
• OBD2 Codes:
  • P0411 – Insufficient Air Flow
  • P2430 – Secondary Air Injection (AIR) System Pressure Sensor Circuit
  • P2431 – Secondary Air Injection System Pressure Sensor A Circuit Range/Performance
  • P2433 – Air Injection System Pressure Sensor A Circuit High

Other OBD2 Codes + Test Results None mentioned.

Mechanic Suggestions

• Inspect for incorrect hose installation, potentially causing moisture ingress into the air pump.
• Replace the check valve and air pump.
• Check for additional damage to wiring connectors or relays, which may be corroded or burnt.
• Normal diagnostics may involve replacing the entire system, including the AIR pump, check valve/solenoid, wiring connectors, and relays.
• Reflash the ECM if normal diagnostics do not isolate the problem.

Final Fix Replaced both the check valve and air pump to restore functionality to the air system.

Case #3: Ford

Vehicle Information 2015 Ford Focus SE 2.0L

Issue + Repair History

• Check engine light illuminated.
• Code P2433 detected, indicating a problem with the secondary air injection system.
• No previous repair history related to this issue.

Other OBD2 Codes + Test Results

• No additional OBD2 codes mentioned.
• Live data shows normal sensor readings.

Mechanic Suggestions

• Inspect the secondary air injection system for leaks or blockages.
• Check the integrity of electrical connections related to the system.
• Perform a smoke test to identify any leaks in the system.
• Consider replacing the secondary air injection pump if no other issues are found.

Final Fix After thorough inspection, it was found that the secondary air injection pump was faulty. Replacing the pump resolved the issue, and the code P2433 was successfully cleared.

Diagnostic Step	Brief Explanation
Inspect the secondary air system	Look for leaks, blockages, or incorrect hose setups that could cause issues.
Check electrical connections	Ensure wires and connectors are in good condition, without corrosion or damage.
Perform a smoke test	Identify any unseen leaks within the system that might be causing problems.
Replace faulty components	Swap out damaged parts like the air pump, check valve, or the sensor itself.
Reflash the ECM	Update the engine control module’s software if other fixes don’t solve the issue.
Create a jumper harness	For specific cases, bypassing damaged wiring directly to the ECM can resolve persistent codes.

These steps are distilled from real-life service cases, emphasizing the importance of thorough diagnostics and tailored repairs. The ultimate goal is to restore the efficiency and emissions performance of the vehicle, ensuring it runs smoothly and within environmental standards.