P2063

Code

Generic P — Powertrain

Reductant/Regeneration Supply Control Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 40 RU: 27

AI status

Completed

ready

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Page language: EN

Causes

Open or short in wiring harness to reductant pump or pump driver
Poor or corroded electrical connector at pump or module
Failed reductant dosing pump or pump motor
Blown fuse or faulty relay supplying the pump
Low battery or weak charging system causing low supply voltage
Control module (ECM/PCM) driver fault

Symptoms

Malfunction Indicator Lamp (MIL) / check engine light illuminated
Reduced or inhibited DPF/SCR regeneration or active regeneration failures
Reduced engine power or limp-home mode on some vehicles
Warning message indicating DEF/AdBlue/urea system fault
Possible drivability issues when regeneration is required

What to check

Read and record DTCs and freeze-frame data with a scan tool. Note conditions when code set.
Check vehicle battery voltage and charging system; ensure >= 12 V with engine off and ~13.5–14.5 V with engine running.
Visually inspect wiring and connectors for damage, corrosion, bent pins, or moisture at pump, relay, and module.
Verify fuses and relays for the reductant pump circuit; inspect and test relay operation.
Backprobe pump connector: check for supply voltage, ground, and control signal with key on and while requesting pump operation via scan tool.
Measure pump motor resistance (with connector disconnected) and compare to manufacturer spec; check for open or short.

Signal parameters

Expected battery supply to pump: approx. 12 V (key on) to charging voltage when running (~13.5–14.5 V).
Control driver output when active: either switched ground or PWM signal; low-logic fault means near 0 V when inactive/low.
Pump motor resistance (typical range): low ohms to tens of ohms (consult vehicle spec).
Current draw when pump running: varies by pump; significantly higher or zero indicates motor fault or short.
Short-to-ground indication: near 0 V on supply line when circuit should be at battery voltage.

Diagnostic algorithm

Retrieve DTCs and freeze-frame data. Note conditions (engine speed, temperature, DEF level) when code set.
Clear codes, perform functional test (command reductant pump with scan tool) and observe if code returns and under what conditions.
With ignition ON, measure voltage at the reductant pump power pin. If no battery voltage, check fuse and relay in supply circuit and repair/replace as needed.
Backprobe control/driver pin while commanding pump. If driver is a switched ground, verify it pulses to ground when commanded. If there is no activity, proceed to wiring/module checks.
Disconnect pump and measure motor resistance. If open or shorted relative to spec, replace pump assembly.
Check continuity and resistance between pump connector and PCM connector for supply, ground and control wires. Repair any opens, high resistance, or shorts to ground/power.
Inspect and clean connectors; repair corrosion or damaged pins. Re-seat connectors and test again.
If wiring and pump test good but driver never activates or shows diagnostic fault, test/replace relay if applicable. If relay and wiring are OK, suspect ECM/PCM driver fault and follow manufacturer procedures to verify or replace module.
After repairs, clear codes and perform a full system test including commanded pump operation and a regeneration cycle if safe. Monitor for return of the code.

Likely causes

Failed reductant dosing pump or pump motor
Blown fuse or faulty relay in the pump supply circuit
Corroded/loose connector or poor ground at pump
Wiring shorted to ground or open circuit between pump and module
ECM/PCM output driver failure

Fault status

⚠️ Status

Reductant/regeneration supply control circuit voltage is below expected threshold. System detected low or absent control/supply signal to reductant pump driver — possible pump, wiring, fuse/relay, or module fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-3.0 hours