What Does P2438 Mean?
The PCM has detected a voltage signal from the secondary air injection system air flow or pressure sensor on Bank 2 that exceeds the expected threshold. This typically indicates an open circuit, short to voltage, or sensor malfunction causing abnormally high readings.
Common Causes
35%
Failed secondary air pressure/flow sensor on Bank 2 reading high
30%
Open circuit in Bank 2 sensor signal or ground wire
20%
Short to voltage in Bank 2 sensor signal circuit
10%
Poor sensor ground connection on Bank 2
5%
Failed PCM (rare)
Diagnostic Steps
1
Step 1: Inspect Bank 2 secondary air pressure sensor connector and wiring for damage, corrosion, or signs of shorts to power
2
Step 2: Using a multimeter, measure sensor signal voltage at the Bank 2 sensor connector with key on, engine off
3
Step 3: Check Bank 2 sensor ground circuit for proper continuity to chassis/PCM ground (should be <0.5 ohms resistance)
4
Step 4: Disconnect Bank 2 sensor and check signal wire voltage at PCM connector (should read approximately 5V with sensor disconnected)
5
Step 5: If wiring tests properly, replace Bank 2 secondary air pressure sensor and verify system operation
Estimated Repair Cost
$150 - $400
Parts + labor, varies by vehicle and location
The PCM has detected a voltage signal from the secondary air injection system air flow or pressure sensor on Bank 2 that exceeds the expected threshold. This typically indicates an open circuit, short to voltage, or sensor malfunction causing abnormally high readings.
The most common cause of P2438 (Secondary Air Injection System Air Flow/Pressure Sensor Circuit High Bank 2) is: Failed secondary air pressure/flow sensor on Bank 2 reading high
Typical repair costs for P2438 range from $150 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive. This fault affects emissions compliance and may cause increased cold-start emissions and failure of emissions testing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P2438 to identify the root cause.
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Quick Info
Category
Powertrain
System
Emissions Control System - Secondary Air Injection
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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