EEb External gas valve error - valve not energized when it should be

What the control is telling you

During a heat call the control does not see voltage at the gas valve when it should. Flowcharts call this code Eb. Note: the wiring diagram legend labels this code 'Internal Gas Valve Error' while the troubleshooting chart and flowchart say external (valve not powered) - follow the chart.

Applies to: Goodman/Amana/GMC gas furnaces, 9-speed ECM, 7-segment control. Two-stage 96%: AC9C96, AM9C96, GC9C96, GM9C96. Single stage 80%: VC9S80, VM9S80, AC9S80, AM9S80, GC9S80, GM9S80. Single stage 92/96%: VC9S96, VM9S96, AC9S96, AM9S96, AM9S92, GC9S96, GM9S96, GM9S92

Likely causes

• Miswired or loose gas valve harness
• Gas valve coil shorted to ground
• Open front cover pressure switch on 90% models (it is in series with the valve)
• Failed control board output

Test and repair steps

1. Check the gas valve wiring against the wiring diagram and correct any miswiring.
2. Remove the wires from the gas valve and check the valve for a short to ground; replace a shorted valve.
3. With a call for heat and the igniter on, check for 24 VAC between the valve wires (MV/MVL and common) at the harness connector on the control board.
4. Voltage at the board but not at the valve: check the harness and, on 90% models, the front cover pressure switch in series with the valve.
5. No voltage at the board output during trial for ignition: replace the integrated control board.
6. If the valve voltage does not match transformer voltage, look for a grounding problem.

Settings for these units

• Normal status displays (7-segment) · Goodman/Amana GM9S96/AM9S96
• Normal status displays (7-segment) · Goodman/Amana GM9S80/AM9S80
• Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
• Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96