P20B0 — Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic

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

  1. Read the code and freeze frame Connect an OBD2 scanner, confirm P20B0 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. 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.
  3. Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the reductant metering unit temperature sensor circuit intermittent/erratic for damage, corrosion, chafing or poor contact.
  4. Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
  5. Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
  6. Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P20B0 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P20B0 (parts and labor, USD, independent shop rates): Repair wiring or connectors: $80–$250; Control module repair: $300–$1,000; Replace the faulty sensor or actuator: $150–$500. Overall, fixing P20B0 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 P20B0?

The most common causes are: corroded, loose or damaged connector, control module driver fault, poor ground connection.

Will P20B0 clear itself?

Sometimes P20B0 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 much does it cost to fix P20B0?

Repair wiring or connectors — $80–$250; Control module repair — $300–$1,000; Replace the faulty sensor or actuator — $150–$500. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What does OBD2 code P20B0 mean?

Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic (P20B0): a powertrain (engine/transmission) fault affecting the sensor and actuator circuits. The car is usually drivable while you plan the repair. Most often caused by corroded, loose or damaged connector, control module driver fault, poor ground connection.

How do I diagnose P20B0 myself?

Start with a scan: confirm P20B0, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the sensor and actuator circuits, and verify the suspect component against live data before buying parts.

What does P20B0 mean?

P20B0 (Reductant Metering Unit Temperature Sensor Circuit Intermittent/Erratic) is stored when self-diagnostics detect abnormal readings or behaviour of the sensor and actuator circuits. It belongs to the powertrain (engine/transmission) category.

To set P20B0, the control module compares live readings of the sensor and actuator circuits against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

What causes P20B0?

  • corroded, loose or damaged connector
  • faulty sensor or actuator of the affected circuit
  • poor ground connection
  • blown fuse feeding the circuit
  • open or shorted wiring in the circuit
  • control module driver fault

Common symptoms of P20B0

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

How to diagnose P20B0

  1. Connect an OBD2 scanner, confirm P20B0 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
  2. 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.
  3. Visually inspect the wiring harness and connectors related to the reductant metering unit temperature sensor circuit intermittent/erratic for damage, corrosion, chafing or poor contact.
  4. Measure reference voltage, ground and signal continuity at the component connector.
  5. Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
  6. Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P20B0 does not return.

How to fix P20B0

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

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

How much does it cost to fix P20B0?

Repair cost depends on which component actually failed. Typical scenarios for P20B0 (parts and labor, USD, independent shop rates):

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

Overall, fixing P20B0 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 P20B0?

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.

Related OBD2 codes