Goodman GMVM970803BN Error Code E6: Low Flame Signal
What Does Code E6 Mean?
An E6 code on the Goodman GMVM970803BN is a warning that the flame sensor is producing a weaker-than-normal microamp signal. Unlike most error codes, E6 does not shut down the furnace — the unit continues to operate normally for now. However, this early warning should not be ignored: if the signal continues to degrade, the control module will eventually be unable to detect flame at all, and the furnace will lock out with an E0 code.
The flame sensor is a metal probe that sits in the burner flame and uses the principle of flame rectification to confirm a flame is present. Over time, the probe develops a coating of oxidation or carbon buildup that electrically insulates it from the flame, reducing the microamp current it can generate. A healthy sensor typically produces 2–6 microamps; when the signal drops below the control board's warning threshold, E6 appears. Other contributing factors include the sensor being positioned incorrectly so it is not fully immersed in the flame, a weak burner flame caused by low gas manifold pressure, or insufficient combustion air reaching the burners.
A technician should clean the flame sensor with a Scotch-Brite pad to remove oxidation, verify the flame signal strength with a multimeter capable of reading microamps, check sensor alignment in the flame, and inspect combustion air piping for blockages. Addressing E6 promptly prevents a future E0 lockout.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- Schedule service soon — a technician should clean the flame sensor, measure the microamp signal, and verify proper sensor alignment and gas manifold pressure before this warning escalates to an E0 lockout
- The technician should also check combustion air piping for blockages and compare the furnace gas input to the rating plate specifications to rule out a lazy flame as the cause of the low signal
✓ Verified against manufacturer service manual — March 2026