P209C — Reductant Injection Air Pressure Sensor B Circuit Low

What Does P209C Mean?

P209C is a diagnostic trouble code indicating: Reductant Injection Air Pressure Sensor B Circuit Low. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.

Symptoms of P209C

⚠️ Check Engine Light (MIL) illuminated
⚠️ Reductant Injection Air Pressure Sensor B reading at zero or minimum value
⚠️ Related system not functioning or in fail-safe mode
⚠️ Reduced engine performance

Common Causes

🔍 Open or broken wire in Reductant Injection Air Pressure Sensor B circuit
🔍 Poor ground connection at Reductant Injection Air Pressure Sensor B
🔍 Faulty Reductant Injection Air Pressure Sensor B with no output signal
🔍 Disconnected or loose Reductant Injection Air Pressure Sensor B connector
🔍 Blown fuse in related circuit

Frequently Asked Questions

What does P209C mean?

P209C indicates: Reductant Injection Air Pressure Sensor B Circuit Low. The vehicle's computer has detected that the Reductant Injection Air Pressure Sensor B is not operating within its expected parameters and stored this diagnostic trouble code.

Can I drive with code P209C?

You can drive short distances for essential trips, but schedule a diagnosis soon. Driving with P209C for extended periods may cause additional problems.

How much does it cost to fix P209C?

Repair costs for P209C typically range from $20 to $300, depending on the root cause. Simple wiring or connector repairs are on the lower end, while component replacement costs more. A proper diagnosis ($80–$150 at most shops) will identify the exact cause before committing to expensive parts.

What To Do Next

Possible Fixes

🔧 Repair broken wire or restore ground in Reductant Injection Air Pressure Sensor B circuit
🔧 Clean and secure Reductant Injection Air Pressure Sensor B connector and ground points
🔧 Replace failed Reductant Injection Air Pressure Sensor B

1
Find your vehicle above
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.

P209C: Reductant Injection Air Pressure Sensor B Circuit Low