Known Characteristic: Heat-Related Error 1 / Error 2 Low Driver on 36M/72M Modules [INTERNAL]

INTERNAL USE ONLY

Issue Summary

Customers using 36M or 72M modules on hot days (especially in June, July, and August, and most often reported mid to late afternoon) may see an Error 1 Low Driver or Error 2 Low Driver error on the module display after the module has been sitting in direct sunlight for an extended period. The error is temperature-driven and resolves on its own as the module cools. It is not a hardware defect, a firmware bug, or something the customer did wrong.

Cause

The high-side FETs in the 36M/72M module electronics become more temperature-sensitive as the ambient temperature climbs and the module heats up in direct sun. That increased sensitivity is what trips the module's internal error check and displays the Error 1 Low Driver or Error 2 Low Driver error. Once the module cools back into its normal operating window (indirect sunlight, shade, or sunset temperatures), the FETs return to normal sensitivity and the code clears on its own.

Rule-Out for Error 1: Voltage Mode

Voltage mode mismatch is the more common cause of Error 1 Low Driver outside of a heat wave, and it is worth confirming before closing a ticket as heat-related. Have the customer confirm their module's voltage mode matches their power source (COBRA LiPo, external SLA, 9V, etc.) using the steps in 36M/72M Voltage Mode. Also worth referencing the existing customer-facing article My 36M/72M is showing 'Error: 1 Low Driver', what does this mean?, which walks the customer through the voltage-mode check first.

If the voltage mode is correct and the error still appears in heat and clears once the module has cooled, that is the thermal characteristic covered by this article. If changing the voltage mode clears the error, that is the fix and no further action is needed.

Error 2 Low Driver is typically NOT voltage-mode related. For Error 2, thermal is almost always the cause once the other basics (LED continuity check, wire seating, etc.) are confirmed.

What the Customer Should Do

• Nothing is required. As the sun starts to set and the ambient temperature drops, the module cools naturally and the error clears. By showtime the module will function normally.
• If the customer wants to keep working with the module while it is hot, they can shade it (a tarp, blanket, cooler lid, anything opaque) or move it into an air-conditioned space for 20 to 30 minutes. Either speeds up the cooldown.

Talking Points for the Customer

• Lead with reassurance. This is a known thermal characteristic of the 36M/72M electronics. The module is not damaged and does not need to be replaced.
• Explain the mechanism in plain language. As the module heats up in direct sun, the internal circuit becomes more temperature-sensitive and triggers the error display. Once it cools it clears on its own.
• Set the expectation for showtime. Even if the customer sees the code in the afternoon, the module will be cooled and clear by the evening.
• Offer the passive fix. Sun sets, module cools, code clears.
• Offer the active fix. Shade or move the module to a cooler location if they want to test or work with it sooner.

What NOT to Do or Say

• Do NOT recommend a firmware reflash. This is not a firmware issue.
• Do NOT open a warranty replacement or repair RMA for a heat-related Error 1 Low Driver or Error 2 Low Driver. The module is not defective. Opening an RMA here creates unnecessary swap cycles at peak season.
• Do NOT describe this as a defect or bug to the customer. It is expected thermal behavior.

When to Escalate

Escalate to L2 for hardware review if the Error 1 Low Driver or Error 2 Low Driver error persists after the module has fully cooled (moved indoors overnight, or out of direct sun for several hours, and the ambient temp is normal). In that scenario document the following before escalating:

• Approximate ambient temperature when the code first appeared
• How long the module has been cooling and where (shade, indoors, AC, overnight, etc.)
• Module history: serial number if available, purchase date, any prior known issues on the account
• Whether the customer has other 36M/72M modules on the same site that are behaving normally

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