Reductant Pump Control Range/Performance
The P208B code indicates that the powertrain control module (PCM) has detected a malfunction in the reductant pump control circuit, specifically a range or performance issue. This pump is responsible for delivering diesel exhaust fluid (DEF) to the selective catalytic reduction (SCR) system to reduce NOx emissions. The code sets when the pump's actual performance deviates from the expected parameters, such as flow rate or pressure, often due to electrical faults, mechanical failures, or contamination.
1. Most Common Causes
- Faulty reductant pump
- Wiring or connector issues in the pump circuit
- Contaminated or crystallized DEF fluid
- Blown fuse or relay for the pump
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or limp mode
- Increased NOx emissions
- Possible DEF warning message on dashboard
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for related codes.
Step 2: Inspect the reductant pump wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the pump's voltage supply and ground circuits with a multimeter.
Step 4: Check the DEF fluid level and quality; replace if contaminated.
Step 5: If all else is fine, replace the reductant pump.
4. 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 reduced engine performance, increased emissions, and potential damage to the SCR system. In some vehicles, it may trigger a derate or limp mode.
How much does it cost to fix?▼
The cost to diagnose and repair a P208B code typically ranges from $50 to $150 for diagnosis, plus parts and labor for pump replacement if needed, which can add $200-$500.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.