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DTC codes / P20xx · Fuel and air metering and auxiliary emission controls / P2062

P2062Reductant Supply Control Circuit/Open

P2062 indicates that the powertrain control module (PCM) has detected an open circuit or supply control fault in the reductant supply circuit, which is part of the diesel exhaust fluid (DEF) system on diesel vehicles. The PCM monitors the control circuit for the reductant supply pump or valve and sets this code when the expected voltage or current is outside the normal range, indicating a break or control issue in the wiring or component.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaFuel and air metering and auxiliary emission controls

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Reductant (DEF) low-level warning or service message displayed on the dashboard
  • Reduced engine power or limp mode if the system enters a fail-safe strategy
  • Difficulty starting the engine or rough running in some cases
  • Increased diesel exhaust fluid consumption or failure to prime the system
  • Emissions-related warning messages or inability to complete a regeneration cycle

Common causes, most likely first

  1. Open or damaged wiring in the reductant supply control circuit, such as a broken wire or corroded connector
  2. Faulty reductant supply pump or control valve solenoid
  3. Blown fuse or relay supplying power to the reductant control circuit
  4. Poor electrical connection at the PCM or reductant control module
  5. Failed reductant control module (if equipped separately from the PCM)
  6. Internal PCM driver failure for the reductant supply circuit

How to diagnose and fix it

  1. Perform a visual inspection of the reductant supply circuit wiring and connectors for damage, corrosion, or loose pins
  2. Check all fuses and relays related to the reductant supply system and replace any that are blown or faulty
  3. Use a scan tool to command the reductant supply pump on and off while monitoring live data to confirm circuit operation
  4. Measure resistance and voltage on the control circuit at the pump and at the PCM to identify opens or shorts
  5. Test the reductant supply pump or valve directly with a known-good power source to verify functionality
  6. If wiring and components test good, check for technical service bulletins (TSBs) or software updates for the PCM
  7. Replace the faulty reductant supply pump, control module, or repair wiring as needed, then clear codes and verify repair

Don't overlook the reductant supply circuit

  • A common mistake is replacing the reductant pump without first checking the wiring harness for chafing or corrosion, which often causes this code.
  • The code can be set by a simple blown fuse that also powers other circuits, so always check fuses before condemning expensive components.
  • On some vehicles, the reductant supply control circuit is integrated into the PCM, and a failed driver may require PCM replacement or reprogramming.
  • Intermittent open circuits can be caused by loose connector pins that only lose contact under vibration or temperature changes, so wiggle-test wiring while monitoring live data.
  • This code does not always mean the pump is dead; a faulty relay or poor ground connection can produce the same open-circuit condition.

Can I keep driving with P2062?

You can usually continue driving with P2062, but the vehicle may enter limp mode or fail emissions testing, so avoid long trips and schedule diagnosis soon. Do not ignore the code, as prolonged driving with a reductant system fault can lead to further emissions system damage or reduced fuel economy.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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