Reductant/Regeneration Supply Control Circuit Low
The P2063 code indicates that the powertrain control module (PCM) has detected a low voltage condition in the reductant/regeneration supply control circuit. This circuit is responsible for controlling the supply of diesel exhaust fluid (DEF) or regeneration fuel to the aftertreatment system. A low voltage reading suggests a short to ground, open circuit, or faulty component in the circuit, which can impair the vehicle's ability to reduce NOx emissions or perform diesel particulate filter (DPF) regeneration.
1. Most Common Causes
- Short to ground in the reductant supply control circuit wiring
- Open circuit or excessive resistance in the reductant actuator wiring
- Faulty reductant supply pump (DEF dosing module)
- Corroded or loose electrical connections in the reductant circuit
- Internal ECM failure (less common)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine performance or power
- Increased exhaust emissions
- Possible regeneration system malfunction
- Fuel economy decrease
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 wiring and connectors for damage, corrosion, or loose connections.
Step 3: Test the control circuit voltage with a multimeter to confirm low voltage condition.
Step 4: Check for shorts to ground or opens in the circuit using a wiring diagram.
Step 5: If wiring is intact, test the reductant/regeneration supply control module per manufacturer specs.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can lead to reduced performance, increased emissions, and potential damage to the aftertreatment system. Have it diagnosed promptly.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for diagnosis and repair, but can be higher if the control module needs replacement.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.