OBD Guide

U066C

Lost Communication With Exhaust Heat Exchanger Bypass Valve Actuator B

U066C is an OBD-II diagnostic trouble code meaning: Lost Communication With Exhaust Heat Exchanger Bypass Valve Actuator B. Common causes: open or short circuit in valve circuit, solenoid valve malfunction. Estimated repair cost: $28–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$28–89 (est.)

Symptoms

  • Check Engine light comes on
  • Deterioration of interior heating in cold weather
  • Increased fuel consumption
  • Unstable engine operation when cold

Causes

  • Open or short circuit in valve circuit
  • Solenoid valve malfunction
  • Problems with the connector or wiring harness
  • Engine control unit malfunction
  • Contact corrosion

How to Fix

  1. Check valve control circuit integrity
  2. Check the resistance and operation of the solenoid valve
  3. Inspect connectors and wiring harness for damage
  4. Clean contacts from corrosion
  5. Replace valve if necessary

Related codes

Error U066C by Vehicle Brand

FAQ

What does the U066C code mean?

U066C is an OBD-II diagnostic trouble code that indicates: Lost Communication With Exhaust Heat Exchanger Bypass Valve Actuator B

What causes a U066C error code?

The most common causes of U066C include: Open or short circuit in valve circuit; Solenoid valve malfunction; Problems with the connector or wiring harness; Engine control unit malfunction.

How do I fix a U066C diagnostic trouble code?

To fix U066C: Check valve control circuit integrity. Check the resistance and operation of the solenoid valve. Inspect connectors and wiring harness for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U066C?

Yes, but get it checked soon

How much does it cost to fix U066C?

The estimated repair cost for U066C is $28–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat