OBD Guide
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C2421

Motor Temperature Sensor Low Input

C2421 is an OBD-II diagnostic trouble code meaning: Motor Temperature Sensor Low Input. Common causes: faulty engine temperature sensor, open or short circuit in wiring harness. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–89 (est.)

Symptoms

  • Incorrect temperature readings on the dashboard
  • Deterioration in acceleration dynamics
  • Increased fuel consumption
  • Difficulty starting in cold weather
  • Activating engine emergency mode

Causes

  • Faulty engine temperature sensor
  • Open or short circuit in wiring harness
  • Poor contact in the sensor connector
  • Contact corrosion
  • ECU problems (rare)

How to Fix

  1. Check the resistance of the temperature sensor at different temperatures (compare with the nominal value)
  2. Inspect the wiring harness for damage
  3. Check voltage and continuity
  4. Clean connector contacts
  5. Replace sensor if necessary

Related codes

P0115P0116P0117P0118

FAQ

What does the C2421 code mean?

C2421 is an OBD-II diagnostic trouble code that indicates: Motor Temperature Sensor Low Input

What causes a C2421 error code?

The most common causes of C2421 include: Faulty engine temperature sensor; Open or short circuit in wiring harness; Poor contact in the sensor connector; Contact corrosion.

How do I fix a C2421 diagnostic trouble code?

To fix C2421: Check the resistance of the temperature sensor at different temperatures (compare with the nominal value). Inspect the wiring harness for damage. Check voltage and continuity. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C2421?

Limited driving only, diagnose soon

How much does it cost to fix C2421?

The estimated repair cost for C2421 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat