OBD Guide
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P0078

Exhaust Valve Control Solenoid Circuit Bank 1

P0078 is an OBD-II diagnostic trouble code meaning: Exhaust Valve Control Solenoid Circuit Bank 1. Common causes: faulty exhaust valve control solenoid, open or short circuit in solenoid wiring. Estimated repair cost: $89–278.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$89–278 (est.)

Symptoms

  • Unstable engine idling
  • Reduced engine power
  • Increased fuel consumption
  • Check Engine Light Illuminates
  • Engine roughness when starting
  • Loss of traction when accelerating
  • Increased emissions

Causes

  • Faulty exhaust valve control solenoid
  • Open or short circuit in solenoid wiring
  • Oxidized or damaged connector pins
  • Engine ECU malfunction
  • Solenoid power problems
  • Mechanical fault of the phase change system
  • Contamination of oil channels of the VVT system

How to Fix

  1. Connect the diagnostic scanner and read the error codes
  2. Check the condition of the solenoid connector and wiring
  3. Measure the solenoid resistance (usually 6-12 ohms)
  4. Check for 12V power supply to the solenoid
  5. Inspect the solenoid for mechanical damage
  6. If necessary, replace the solenoid
  7. Check and clean the oil passages of the VVT system
  8. Clear error codes and test drive

Related codes

P0077P0079P0080P0011P0021P0010P0020

Error P0078 by Vehicle Brand

AcuraAudiBAICBMWBYDBuickCadillacChanganCheryChevroletChryslerCitroenDodgeDongfengExeedFAWFordForthingFotonGACGMGMCGeelyGreat WallHavalHondaHongqiHyundaiInfinitiJACJaecooJaguarJeepJetourKaiyiKiaLadaLexusLi AutoLifanLincolnLivanMazdaMercedes-BenzMercuryMitsubishiNIONissanOldsmobileOmodaOpelPeugeotPlymouthPontiacRenaultSWMSaturnSkodaSkywellSubaruSuzukiTankToyotaVolkswagenVolvoVoyahXPengZeekrZotye

FAQ

What does the P0078 code mean?

P0078 is an OBD-II diagnostic trouble code that indicates: Exhaust Valve Control Solenoid Circuit Bank 1

What causes a P0078 error code?

The most common causes of P0078 include: Faulty exhaust valve control solenoid; Open or short circuit in solenoid wiring; Oxidized or damaged connector pins; Engine ECU malfunction.

How do I fix a P0078 diagnostic trouble code?

To fix P0078: Connect the diagnostic scanner and read the error codes. Check the condition of the solenoid connector and wiring. Measure the solenoid resistance (usually 6-12 ohms). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P0078?

Limited driving only, diagnose soon

How much does it cost to fix P0078?

The estimated repair cost for P0078 is $89–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat