OBD Guide

U1291

MICU Lost Communication With Relay Control Module

U1291 is an OBD-II diagnostic trouble code meaning: MICU Lost Communication With Relay Control Module. Common causes: broken or damaged wires between micu and relay module, relay control module failure. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Failure to operate elements controlled via a relay (headlights, power windows, etc.)
  • Malfunction indicator light comes on
  • Unstable operation of electrical equipment
  • Errors in other system modules

Causes

  • Broken or damaged wires between MICU and relay module
  • Relay control module failure
  • Relay Module Power Problems
  • Corrosion or oxidation of contacts in connectors
  • Malfunction of the MICU itself

How to Fix

  1. Check the integrity of the wiring harness between the modules
  2. Inspect connectors for corrosion and damage
  3. Check power supply to relay module
  4. Diagnose the MICU and relay module
  5. If necessary, replace the faulty module or wiring

Related codes

FAQ

What does the U1291 code mean?

U1291 is an OBD-II diagnostic trouble code that indicates: MICU Lost Communication With Relay Control Module

What causes a U1291 error code?

The most common causes of U1291 include: Broken or damaged wires between MICU and relay module; Relay control module failure; Relay Module Power Problems; Corrosion or oxidation of contacts in connectors.

How do I fix a U1291 diagnostic trouble code?

To fix U1291: Check the integrity of the wiring harness between the modules. Inspect connectors for corrosion and damage. Check power supply to relay module. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U1291?

Yes, but get it checked soon

How much does it cost to fix U1291?

The estimated repair cost for U1291 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat