OBD Guide
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P0597

Thermostat Heater Control Circuit/Open

P0597 is an OBD-II diagnostic trouble code meaning: Thermostat Heater Control Circuit/Open. Common causes: broken wire in the thermostat heater circuit, oxidation or poor contact in the thermostat connector. Estimated repair cost: $22–111.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$22–111 (est.)

Symptoms

  • Check Engine light is on
  • Extended engine warm-up time
  • Increased fuel consumption
  • The engine runs at a reduced operating temperature
  • Poor performance of the interior heater

Causes

  • Broken wire in the thermostat heater circuit
  • Oxidation or poor contact in the thermostat connector
  • Faulty thermostat heating element
  • Damaged ECU connector
  • ECU malfunction (rare)

How to Fix

  1. Read all error codes and document additional codes
  2. Inspect the thermostat connector and wiring for damage, corrosion, or breaks.
  3. Measure the supply voltage at the thermostat connector with the ignition on
  4. Check the resistance of the thermostat heating element (compare with specification)
  5. Check the integrity of the control circuit from the computer to the thermostat
  6. Replace the thermostat if a heater malfunction is detected
  7. Reset codes and test drive to check

Related codes

P0598P0599P0128P0125P0115

Error P0597 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0597 code mean?

P0597 is an OBD-II diagnostic trouble code that indicates: Thermostat Heater Control Circuit/Open

What causes a P0597 error code?

The most common causes of P0597 include: Broken wire in the thermostat heater circuit; Oxidation or poor contact in the thermostat connector; Faulty thermostat heating element; Damaged ECU connector.

How do I fix a P0597 diagnostic trouble code?

To fix P0597: Read all error codes and document additional codes. Inspect the thermostat connector and wiring for damage, corrosion, or breaks.. Measure the supply voltage at the thermostat connector with the ignition on. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0597?

Do not drive — repair immediately

How much does it cost to fix P0597?

The estimated repair cost for P0597 is $22–111. Actual cost depends on your vehicle, location, and labor rates.

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