What This Error Means

The furnace repeatedly reached the point in the ignition sequence when the gas valve should have been energized, but the control did not detect the expected gas-valve operation.

Symptoms You May Notice

Inducer runs; igniter may heat; burners do not light; repeated ignition attempts; no gas-valve click; furnace eventually locks out.

Common Causes

Loose gas-valve connector; open gas-valve coil; damaged wiring; failed control-board gas-valve output; low control voltage; open safety circuit; faulty gas valve.

Safe Troubleshooting Steps

1. Turn off power and gas. 2. Inspect the gas-valve plug and wiring for damage or loose connections. 3. Confirm all furnace safety circuits are closed as required. 4. A qualified technician should verify control voltage at the valve during the ignition sequence. 5. Test gas-valve coil resistance according to service data. 6. If voltage is absent, diagnose the control board and upstream safety circuit. 7. If correct voltage is present but the valve does not operate, replace the valve using approved procedures.

Parts Commonly Involved

Gas valve; integrated furnace control; transformer; safety switches; wiring harness; igniter.

When to Call a Technician

Yes. Gas-valve and live-voltage testing should be performed by a qualified HVAC professional.

Safety Notice

Do not apply external power to a gas valve or attempt gas-valve replacement without proper training, leak testing and combustion verification.

Manufacturer Documentation