Reductant Injection Air Pump Control Circuit/Open
The P2059 code indicates a problem in the electrical circuit that controls the reductant injection air pump, which is part of the Selective Catalytic Reduction (SCR) system. This pump supplies air to help atomize diesel exhaust fluid (DEF) before it enters the exhaust stream. An open circuit means there is a break in the wiring or a faulty component, preventing the pump from operating correctly. This can lead to incomplete DEF injection, causing increased NOx emissions and potential damage to the SCR system.
01. Most Common Causes
- Blown fuse or open circuit in the air pump wiring
- Faulty reductant injection air pump relay
- Defective reductant injection air pump motor
- Corroded or damaged electrical connectors
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased exhaust emissions
- Possible DEF system warning messages
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm P2059 and check for related codes.
Step 2: Visually inspect the air pump wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the air pump relay and fuse with a multimeter.
Step 4: Check for voltage at the air pump connector; if no voltage, repair wiring or replace relay/fuse.
Step 5: If voltage is present, test the air pump motor resistance; replace if out of spec.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances with this code, as it can lead to increased emissions and potential damage to the SCR system. The vehicle may enter limp mode, reducing performance.
How much does it cost to fix?▼
The cost to fix P2059 typically ranges from $50 to $150 for parts and labor, depending on the root cause. Replacing a fuse or relay is cheaper, while a new air pump can cost more.