Reductant Pump Control Range/Performance
The P208B code indicates that the Engine Control Module (ECM) has detected a malfunction in the reductant pump control circuit, which is responsible for delivering diesel exhaust fluid (DEF) to the selective catalytic reduction (SCR) system. This can result from the pump not operating within its expected range or performance parameters, often due to electrical issues, pump failure, or wiring problems. The SCR system is critical for reducing NOx emissions, and this fault can lead to reduced engine performance and increased emissions.
01. Most Common Causes
- Faulty reductant pump
- Open or shorted wiring in the pump control circuit
- Poor electrical connections at the pump or ECM
- Failed ECM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power or limp mode
- Increased diesel exhaust fluid consumption
- Failed emissions test
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Inspect the reductant pump and its wiring for damage, corrosion, or loose connections.
Step 3: Test the pump's electrical resistance and voltage supply using a multimeter.
Step 4: If wiring and connections are okay, replace the reductant pump and clear the code.
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 reduced engine performance and potential damage to the SCR system. Additionally, the vehicle may enter limp mode, limiting speed and drivability.
How much does it cost to fix?▼
The cost to fix P208B typically ranges from $50 to $150 for diagnosis and parts, but can be higher if the pump needs replacement, which may cost $200-$500 including labor.