OBD Guide
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P0668

Control Module Internal Temperature Sensor A Circuit Low

P0668 is an OBD-II diagnostic trouble code meaning: Control Module Internal Temperature Sensor A Circuit Low. Common causes: short circuit of the sensor signal wire to ground, open or damaged temperature sensor circuit. Estimated repair cost: $33–889.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$33–889 (est.)

Symptoms

  • The Check Engine light comes on
  • It is possible to switch to emergency engine operation mode
  • Reduced engine power
  • Unstable operation of control systems
  • Difficulty starting the engine in cold weather

Causes

  • Short circuit of the sensor signal wire to ground
  • Open or damaged temperature sensor circuit
  • ECU internal temperature sensor malfunction
  • Oxidation or damage to the ECU connector
  • Internal ECU fault

How to Fix

  1. Read all error codes with an OBD-II scanner and record the data
  2. Visually inspect the wiring and connectors of the ECU for damage, oxidation or breaks
  3. Measure the voltage in the temperature sensor circuit A with a multimeter (standard: 0.5–4.5 V)
  4. Check the sensor resistance and compare with the manufacturer's technical data
  5. Check the circuit for open circuit and short circuit to ground.
  6. If the wiring and sensor are in good condition - diagnostics and replacement of the ECU

Related codes

P0669P0597P0598P0599

Error P0668 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0668 code mean?

P0668 is an OBD-II diagnostic trouble code that indicates: Control Module Internal Temperature Sensor A Circuit Low

What causes a P0668 error code?

The most common causes of P0668 include: Short circuit of the sensor signal wire to ground; Open or damaged temperature sensor circuit; ECU internal temperature sensor malfunction; Oxidation or damage to the ECU connector.

How do I fix a P0668 diagnostic trouble code?

To fix P0668: Read all error codes with an OBD-II scanner and record the data. Visually inspect the wiring and connectors of the ECU for damage, oxidation or breaks. Measure the voltage in the temperature sensor circuit A with a multimeter (standard: 0.5–4.5 V). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0668?

Limited driving only, diagnose soon

How much does it cost to fix P0668?

The estimated repair cost for P0668 is $33–889. Actual cost depends on your vehicle, location, and labor rates.

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