OBD Guide

U3020

Control Module Wake-up Circuit B High

U3020 is an OBD-II diagnostic trouble code meaning: Control Module Wake-up Circuit B High. Common causes: short circuit in wake-up circuit, control unit b fault. Estimated repair cost: $17–111.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–111 (est.)

Symptoms

  • Problems starting the engine
  • The control unit does not activate
  • Errors in other vehicle systems
  • Reduced vehicle performance
  • Check Engine Light Is On

Causes

  • Short circuit in wake-up circuit
  • Control unit B fault
  • Relay or fuse problems
  • Wiring harness damage
  • Grounding problems

How to Fix

  1. Check wake-up circuit for short circuit
  2. Check fuses and relays associated with control unit B
  3. Inspect the wiring harness for damage
  4. Check grounding of control unit B
  5. Replace control unit B if necessary

Related codes

Error U3020 by Vehicle Brand

FAQ

What does the U3020 code mean?

U3020 is an OBD-II diagnostic trouble code that indicates: Control Module Wake-up Circuit B High

What causes a U3020 error code?

The most common causes of U3020 include: Short circuit in wake-up circuit; Control unit B fault; Relay or fuse problems; Wiring harness damage.

How do I fix a U3020 diagnostic trouble code?

To fix U3020: Check wake-up circuit for short circuit. Check fuses and relays associated with control unit B. Inspect the wiring harness for damage. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U3020?

Yes, but get it checked soon

How much does it cost to fix U3020?

The estimated repair cost for U3020 is $17–111. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat