P2063 — Reductant/Regeneration Supply Control Circuit Low

OBD2 code P2063 flags a problem with the sensor and actuator circuits (reductant/regeneration supply control circuit low). The car is usually drivable while you plan the repair. Common culprits: control module driver fault, faulty sensor or actuator of the affected circuit, poor ground connection.

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P2063 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the reductant/regeneration supply control for damage, corrosion, chafing or poor contact.
Subsystem check Check for supply voltage at the reductant/regeneration supply control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2063 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2063 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Replace the faulty sensor or actuator: $150–$500; Control module repair: $300–$1,000. Overall, fixing P2063 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

What is the most common cause of P2063?

The most common causes are: control module driver fault, faulty sensor or actuator of the affected circuit, poor ground connection.

Is it safe to drive with P2063?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

Will P2063 clear itself?

Sometimes P2063 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

How do I diagnose P2063 myself?

Start with a scan: confirm P2063, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the reductant/regeneration supply control, and verify the suspect component against live data before buying parts.

What does OBD2 code P2063 mean?

What does P2063 mean?

P2063 (Reductant/Regeneration Supply Control Circuit Low) is stored when self-diagnostics detect abnormal readings or behaviour of the sensor and actuator circuits. It belongs to the powertrain (engine/transmission) category.

“Circuit low” means the voltage on the reductant/regeneration supply control circuit stays below the expected minimum — close to ground. The usual physical reasons are a short to ground, a chafed wire touching metal, a missing supply voltage, or a failed component dragging the signal down.

This code does not appear from a single bad reading: the module must see the fault condition repeat under defined operating conditions before it turns on the warning light. The freeze frame captured with P2063 — engine load, rpm, temperature, speed — tells you exactly when the problem occurs, so reproduce those conditions when testing.

Common symptoms of P2063

Check Engine Light on
possible limp mode depending on the affected component
increased fuel consumption in some cases
the affected system operates intermittently or not at all

What causes P2063?

signal wire shorted to ground (chafed insulation)
failed reductant/regeneration supply control pulling the signal low
missing supply voltage to the reductant/regeneration supply control
corroded, loose or damaged connector
faulty sensor or actuator of the affected circuit
poor ground connection
open or shorted wiring in the circuit

How to diagnose P2063

Connect an OBD2 scanner, confirm P2063 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the reductant/regeneration supply control for damage, corrosion, chafing or poor contact.
Check for supply voltage at the reductant/regeneration supply control connector first; then measure resistance from the signal wire to ground — near-zero ohms confirms a short to ground in the harness.
Measure reference voltage, ground and signal continuity at the component connector.
Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2063 does not return.

How to fix P2063

Start with the cheapest and most common causes before replacing expensive parts:

Repair wiring or connectors — $80–$250
Replace the faulty sensor or actuator — $150–$500
Control module repair — $300–$1,000

How much does it cost to fix P2063?

Repair cost depends on which component actually failed. Typical scenarios for P2063 (parts and labor, USD, independent shop rates):

Repair wiring or connectors: $80–$250
Replace the faulty sensor or actuator: $150–$500
Control module repair: $300–$1,000

Overall, fixing P2063 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P2063?