Reductant/Regeneration Supply Control Circuit High
P2064 indicates the reductant (DEF/urea) supply control circuit is receiving a higher voltage or current signal than expected. This typically occurs in vehicles with selective catalytic reduction (SCR) systems and suggests a malfunction in the reductant pump circuit, wiring, or related control components. If not addressed, catalyst damage and reduced emissions system performance can result.
What You Might Notice
- Reduced fuel efficiency
- Excessive black smoke from exhaust
- Diminished engine performance
- Check Engine Light illuminated
- Other SCR-related codes present
Most Common Causes
- 1
Defective reductant supply pump
The DEF/urea supply pump may be failing or drawing excessive current, causing an overload condition in the supply circuit.
- 2
Wiring or connector issues
Corroded, damaged, or loose wiring and connectors in the reductant supply circuit can cause abnormal voltage signals.
- 3
Faulty SCR control module
The selective catalytic reduction control unit may be malfunctioning and misreading or misregulating pump voltage.
- 4
Reductant tank or heater malfunction
Issues with the DEF tank heater or tank sensor can cause circuit voltage abnormalities.
How to Diagnose It
- 1
Check Defective reductant supply pump — The DEF/urea supply pump may be failing or drawing excessive current, causing an overload condition in the supply circuit.
- 2
Check Wiring or connector issues — Corroded, damaged, or loose wiring and connectors in the reductant supply circuit can cause abnormal voltage signals.
- 3
Check Faulty SCR control module — The selective catalytic reduction control unit may be malfunctioning and misreading or misregulating pump voltage.
- 4
Check Reductant tank or heater malfunction — Issues with the DEF tank heater or tank sensor can cause circuit voltage abnormalities.
How to Fix It
- 1
Inspect and test reductant pump
Verify pump operation and measure current draw. Replace the pump if it is drawing excessive current or not functioning properly.
- 2
Check wiring and connectors
Inspect all connections in the reductant supply circuit for corrosion, damage, or loose terminals. Clean or replace connectors as needed.
- 3
Test SCR control module
Use diagnostic equipment to test the SCR module's ability to regulate pump voltage. Replace if module is faulty.
- 4
Inspect DEF tank heater and sensor
Test the tank heater and associated sensors for proper function. Replace any faulty components that may be causing circuit voltage issues.
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