OBD Guide

U300D

Ignition Input On/Start

U300D is an OBD-II diagnostic trouble code meaning: Ignition Input On/Start. Common causes: ignition switch malfunction, problems with the ignition circuit wiring or connectors. Estimated repair cost: $6–56.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$6–56 (est.)

Symptoms

  • Engine won't start
  • Difficulty starting the engine
  • Unstable engine operation
  • Check Engine Light Is On
  • Problems with car electrical equipment

Causes

  • Ignition switch malfunction
  • Problems with the ignition circuit wiring or connectors
  • Engine control module (ECU) malfunction
  • Damaged or corroded contacts
  • Low battery voltage

How to Fix

  1. Check the condition of the battery and its voltage
  2. Inspect the ignition circuit wiring and connectors for damage and corrosion.
  3. Check the ignition switch for proper operation
  4. Check the engine control module (ECU) for faults
  5. Replace faulty ignition circuit components

Related codes

Error U300D by Vehicle Brand

FAQ

What does the U300D code mean?

U300D is an OBD-II diagnostic trouble code that indicates: Ignition Input On/Start

What causes a U300D error code?

The most common causes of U300D include: Ignition switch malfunction; Problems with the ignition circuit wiring or connectors; Engine control module (ECU) malfunction; Damaged or corroded contacts.

How do I fix a U300D diagnostic trouble code?

To fix U300D: Check the condition of the battery and its voltage. Inspect the ignition circuit wiring and connectors for damage and corrosion.. Check the ignition switch for proper operation. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with U300D?

Yes, but get it checked soon

How much does it cost to fix U300D?

The estimated repair cost for U300D is $6–56. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat