Reductant Supply Control Circuit High
The P2064 code indicates that the powertrain control module (PCM) has detected a high voltage condition in the reductant/regeneration supply control circuit. This circuit controls the supply of diesel exhaust fluid (DEF) or regeneration fuel to the aftertreatment system. A high voltage reading typically points to a short to power, a faulty control module, or a wiring issue. This can affect the vehicle's ability to reduce NOx emissions and may trigger the check engine light.
1. Most Common Causes
- Short circuit to battery positive (B+) in the reductant pump control/signal wire
- Internal short circuit in the DEF supply pump
- Internal short circuit in the DEF dosing injector control winding
- Corroded, loose, or backed-out connector terminals contacting battery voltage
- Faulty PCM/ECM with internal output driver short circuit (rare)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or limp mode
- Increased emissions
- Possible DEF system warning messages
3. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Visually inspect the reductant supply control circuit wiring and connectors for damage, corrosion, or shorts.
Step 3: Test the circuit voltage with a multimeter to confirm high voltage condition.
Step 4: Check the reductant supply control module/pump for proper operation and replace if faulty.
Step 5: If wiring and components are okay, test the PCM output and consider reprogramming or replacement.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it may cause reduced performance, limp mode, or increased emissions. You should have it diagnosed and repaired promptly.
How much does it cost to fix?▼
The cost typically ranges from $100 to $300 for parts and labor, depending on the root cause and vehicle make/model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.