OBD Guide
ENFRDEESPT

P0634

Control Module Internal Temperature A Too High

P0634 is an OBD-II diagnostic trouble code meaning: Control Module Internal Temperature A Too High. Common causes: incorrect location of the ecu close to heat sources, coolant leak on the ecu housing. Estimated repair cost: $22–556.

Severity
🔴 High
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–556 (est.)

Symptoms

  • The Check Engine light comes on
  • Emergency mode or reduction in engine power
  • Malfunctions of various systems during long driving
  • The code appears after a long period of driving in a traffic jam
  • Possible unstable operation of the ECU at high air temperatures

Causes

  • Incorrect location of the ECU close to heat sources
  • Coolant leak on the ECU housing
  • Engine cooling system malfunction
  • Clogged engine compartment ventilation system
  • Internal defect of the ECU - increased heat generation

How to Fix

  1. Make sure the ECU is positioned correctly and is not near the exhaust manifold
  2. Check the cooling system for leaks and if the engine is overheating
  3. Check for thermal shields near the ECU
  4. Check engine compartment ventilation
  5. At normal engine temperature - diagnostics of the internal ECU sensor
  6. Consider installing an additional heat sink on the ECU housing

Related codes

P0217P0118P0606P0607

Error P0634 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0634 code mean?

P0634 is an OBD-II diagnostic trouble code that indicates: Control Module Internal Temperature A Too High

What causes a P0634 error code?

The most common causes of P0634 include: Incorrect location of the ECU close to heat sources; Coolant leak on the ECU housing; Engine cooling system malfunction; Clogged engine compartment ventilation system.

How do I fix a P0634 diagnostic trouble code?

To fix P0634: Make sure the ECU is positioned correctly and is not near the exhaust manifold. Check the cooling system for leaks and if the engine is overheating. Check for thermal shields near the ECU. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0634?

Limited driving only, diagnose soon

How much does it cost to fix P0634?

The estimated repair cost for P0634 is $22–556. Actual cost depends on your vehicle, location, and labor rates.

FRDEESPT

See also: Russian version · NationStat