P0079 – Exhaust Valve Control Solenoid Circuit Low (Bank 1)

Description

The P0079 trouble code indicates that the Engine Control Module (ECM) has detected a low voltage condition in the exhaust valve timing control solenoid circuit on Bank 1. The exhaust VVT solenoid controls oil flow to the variable valve timing system, allowing the engine to adjust valve timing for better performance, fuel economy, and emissions control.

Common Causes

Common causes include a faulty exhaust VVT solenoid, shorted wiring to ground, damaged connectors, poor electrical connections, low engine oil pressure, dirty engine oil, or a faulty ECM in rare cases.

Symptoms

Possible symptoms include Check Engine Light illumination, reduced engine power, rough idle, poor acceleration, engine hesitation, and increased fuel consumption.

Estimated Repair Cost

The repair cost usually ranges from $20 to $250, depending on whether the issue requires wiring repair, connector replacement, or replacement of the exhaust VVT solenoid.

Severity

Moderate. The vehicle may continue operating, but ignoring the problem can reduce engine efficiency and affect the proper operation of the variable valve timing system.

Recommended Fix

Inspect the exhaust VVT solenoid and its wiring for damage or corrosion. Check the electrical signal and ground circuit, verify oil condition and level, replace the solenoid if faulty, clear the trouble code, and confirm that the issue does not return.