P0079: Exhaust Valve Control Solenoid Circuit Low Bank 1

What it means

The control module detects a circuit-low condition in the Bank 1 exhaust valve control solenoid circuit.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The bank 1 exhaust valve control solenoid circuit operates a vehicle-specific exhaust valve-control function. P0079 means the control module sees voltage below the expected range in that circuit, which can result from a short to ground or another fault pulling the circuit low.

Common causes

Most likely first.

1. Wiring shorted to ground
2. Connector pins corroded - high contact resistance
3. Harness chafing through insulation

Symptoms

• Check-engine light on
• Reduced engine power
• Rough idle or hesitation
• Poor acceleration

How to diagnose it

1. Save freeze-frame data and check for related exhaust valve-control codes to establish when the low-circuit fault occurs.
2. Locate the bank 1 exhaust valve control solenoid from vehicle service information and inspect its connector and harness for chafing, heat damage, corrosion, or contact with ground.
3. Use the wiring diagram to test the solenoid circuit for a short to ground, following the manufacturer's procedure.
4. Check connector terminals and circuit continuity for poor or damaged connections.
5. Test the solenoid coil against the manufacturer's specification and check for mechanical binding if electrical tests pass.

Common fixes

• Repair wiring shorted to ground in the bank 1 exhaust solenoid circuit.
• Clean or replace corroded or damaged connector terminals.
• Repair chafed or heat-damaged wiring.
• Replace the bank 1 exhaust valve control solenoid if it fails its coil test.

Can I keep driving?

Reduced power or hesitation may affect acceleration, so avoid hard acceleration and high-demand driving until diagnosed. Stop if the engine runs severely rough or loses power in a way that makes driving unsafe.