OBD Guide
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C1774

Coolant Temperature Out of Range

C1774 is an OBD-II diagnostic trouble code meaning: Coolant Temperature Out of Range. Common causes: coolant temperature sensor malfunction, open or short circuit in the sensor circuit. Estimated repair cost: $22–56.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–56 (est.)

Symptoms

  • Unstable engine operation at idle
  • Increased fuel consumption
  • Engine overheating
  • Check Engine Light Illuminates

Causes

  • Coolant temperature sensor malfunction
  • Open or short circuit in the sensor circuit
  • Poor contact in the sensor connector
  • Coolant leak
  • Thermostat malfunction

How to Fix

  1. Check coolant level
  2. Inspect the temperature sensor and its circuit for damage
  3. Check sensor resistance at different temperatures
  4. Replace the coolant temperature sensor if necessary
  5. Check thermostat operation

Related codes

P0115P0116P0117P0118

FAQ

What does the C1774 code mean?

C1774 is an OBD-II diagnostic trouble code that indicates: Coolant Temperature Out of Range

What causes a C1774 error code?

The most common causes of C1774 include: Coolant temperature sensor malfunction; Open or short circuit in the sensor circuit; Poor contact in the sensor connector; Coolant leak.

How do I fix a C1774 diagnostic trouble code?

To fix C1774: Check coolant level. Inspect the temperature sensor and its circuit for damage. Check sensor resistance at different temperatures. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1774?

Limited driving only, diagnose soon

How much does it cost to fix C1774?

The estimated repair cost for C1774 is $22–56. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat