How much does VVT solenoid replacement cost?

VVT solenoid replacement typically costs $150-$400 including parts and labor. The solenoid itself costs $50-$150, and it is usually accessible for a relatively quick replacement.

Can I fix VVT problems with an oil change?

In some cases, yes. If the VVT issue is caused by dirty oil, performing an oil change with the correct grade oil can resolve the code. However, if the solenoid or phaser is damaged, replacement is needed.

P0078

Exhaust Valve Control Solenoid Circuit (Bank 1)

Moderatevariable valve

Overview

The P0078 diagnostic trouble code indicates a exhaust valve control solenoid circuit (bank 1) condition. This code relates to the variable valve timing (VVT) system, which adjusts camshaft timing for optimal performance across the engine's RPM range. VVT issues often stem from oil quality or flow problems and can cause rough idle, poor performance, and decreased fuel economy.

Symptoms

Check Engine Light (MIL) illuminated
Rough or unstable idle
Engine stalling at idle
Engine rattling noise on startup

Common Causes

Wiring issues in VVT solenoid circuit
Dirty or low engine oil
Faulty VVT solenoid/actuator (oil control valve)
Worn timing chain or stretched chain

Diagnosis Steps

1Connect an OBD-II scanner and read all stored trouble codes and freeze frame data
2Check engine oil level and condition; change oil if dirty or incorrect viscosity
3Test the VVT solenoid (oil control valve) with a multimeter
4Inspect the VVT solenoid screen/filter for debris or sludge
5Monitor camshaft position sensor data using scan tool live data

Estimated Repair Cost

$150 — $1,000

Cost varies by vehicle, location, and repair shop. Includes parts and labor.

Commonly Affected Vehicles

Toyota Camry (2.5L)Kia OptimaChevrolet EquinoxBMW 3 Series (VANOS)

Related Codes

P0021 P0012 P0022

More Variable Valve Codes

P0008Engine Position System Performance (Bank 1)

Severe

P0009Engine Position System Performance (Bank 2)

Severe

P0010Intake Camshaft Position Actuator Circuit (Bank 1)

Moderate

P0011Intake Camshaft Position Timing Over-Advanced (Bank 1)

Moderate

P0012Intake Camshaft Position Timing Over-Retarded (Bank 1)

Moderate

P0013Exhaust Camshaft Position Actuator Circuit (Bank 1)

Moderate

Frequently Asked Questions

Yes, dirty or low-quality engine oil is one of the leading causes of VVT system problems. Oil sludge can clog the VVT solenoid screen and oil passages, preventing proper cam timing adjustment.