Secondary Air Injection System Air Flow/Pressure Sensor Circuit High Bank 2
The P2438 code indicates that the Powertrain Control Module (PCM) has detected a high voltage signal from the secondary air injection (SAI) system pressure sensor on Bank 2. This sensor monitors air flow/pressure in the SAI system, which reduces emissions during cold starts by injecting air into the exhaust. A high voltage reading suggests a circuit issue, faulty sensor, or blockage in the system.
01. Most Common Causes
- Faulty secondary air injection pressure sensor
- Short to voltage in sensor circuit
- Blocked or restricted secondary air injection passages
- Failed secondary air injection pump or relay
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Possible rough idle or hesitation on cold start
- Reduced fuel economy
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify P2438 and check for related codes.
Step 2: Inspect the SAI pressure sensor connector and wiring for damage or corrosion.
Step 3: Test the sensor voltage with a multimeter; compare to manufacturer specs.
Step 4: Check for blockages in the SAI system hoses and passages.
Step 5: Test the SAI pump operation and relay function.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, but the vehicle may fail an emissions test and the Check Engine Light will remain on. It's best to diagnose and repair promptly to avoid potential drivability issues.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Sensor replacement ranges from $100-$300, while pump or relay replacement can be $200-$500.