P208D: Reductant Pump Control Circuit High
The P208D code indicates that the powertrain control module (PCM) has detected a high voltage condition in the control circuit of the reductant pump, which is part of the selective catalytic reduction (SCR) system. This pump delivers diesel exhaust fluid (DEF) to the SCR catalyst to reduce NOx emissions. A high voltage reading typically points to a short to power, a faulty pump, or a wiring issue.
01. Most Common Causes
- Short to power in the reductant pump control circuit
- Faulty reductant pump
- Damaged wiring or connectors
- Corroded or loose electrical connections
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or limp mode
- Increased NOx emissions
- Possible DEF system warning messages
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and document freeze frame data.
Step 2: Visually inspect the reductant pump wiring and connectors for damage, corrosion, or loose connections.
Step 3: Use a multimeter to check for voltage at the pump connector; compare to manufacturer specs.
Step 4: Test the reductant pump resistance and operation per service manual.
Step 5: If wiring and pump are okay, check for a short to power in the control circuit and repair as needed.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the SCR system may be disabled, leading to increased emissions and potential engine derating. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and minor repairs like wiring fixes. If the pump needs replacement, parts and labor can add $200-$500.