Reductant/Regeneration Supply Control Circuit/Open
P2062 indicates a problem with the reductant (DEF) supply control circuit in the selective catalytic reduction (SCR) system, typically showing an open or interrupted signal. This code prevents proper injection of reductant fluid, which can lead to catalyst damage and increased emissions if not addressed promptly.
What You Might Notice
- Reduced fuel efficiency
- Excessive black smoke from exhaust
- Diminished engine performance
- Check engine light illumination
- Difficulty starting or rough idle
Most Common Causes
- 1
Defective reductant supply pump
The DEF pump may be faulty, overloaded, or failing to operate properly, preventing reductant from being delivered to the SCR system.
- 2
Open or damaged wiring in supply circuit
Broken, corroded, or disconnected wiring in the reductant pump control circuit can interrupt signal transmission to the pump.
- 3
Faulty pump relay or control module
A defective relay or faulty engine control module (ECM) may fail to send the proper signal to activate the reductant pump.
- 4
Empty or contaminated DEF tank
Low reductant fluid levels or contaminated DEF can trigger supply circuit faults and prevent proper system operation.
How to Diagnose It
- 1
Check Defective reductant supply pump — The DEF pump may be faulty, overloaded, or failing to operate properly, preventing reductant from being delivered to the SCR system.
- 2
Check Open or damaged wiring in supply circuit — Broken, corroded, or disconnected wiring in the reductant pump control circuit can interrupt signal transmission to the pump.
- 3
Check Faulty pump relay or control module — A defective relay or faulty engine control module (ECM) may fail to send the proper signal to activate the reductant pump.
- 4
Check Empty or contaminated DEF tank — Low reductant fluid levels or contaminated DEF can trigger supply circuit faults and prevent proper system operation.
How to Fix It
- 1
Inspect and test reductant pump
Use a diagnostic scanner to verify pump voltage and operation; test pump directly with 12V power to confirm if it is functioning. Replace the pump if it does not respond or operate properly.
- 2
Check and repair wiring and connectors
Inspect the supply pump wiring harness for breaks, corrosion, or loose connections. Clean or repair connectors and re-seat connections; replace wiring if damaged.
- 3
Test and replace pump relay
Locate the reductant pump relay and test it with a multimeter or by swapping with an identical relay. Replace the relay if it does not activate or pass continuity tests.
- 4
Refill and check DEF tank level
Verify DEF fluid level in the reservoir and refill with quality, non-contaminated diesel exhaust fluid. Inspect the tank sensor and top-up valve for blockages or failures.
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