True Refrigerator Error Code E13: Danfoss ETC Communication Error

What does True error code E13 mean?

E13 means the control and the parts it talks to, such as the display or a second control board, are not exchanging signals correctly. The ETC checks that link continuously, and when messages stop arriving it reports a communication error instead of a temperature problem. The cabinet may keep cooling because the main control is still working, or it may behave oddly, with readings that do not match what you expect. The trouble is in the link, not in a single temperature probe, so changing a sensor will not help. Cleaning crews and vibration are common reasons a plug works loose. A technician looks at the cable and connectors first, then at whether any recently replaced part matches the others, and finally at the control board or the display itself.

Affected models and control systems

True cabinets with a current Danfoss ETC display.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

• E13 on the display
• Readings that do not match the cabinet
• Keys that do not respond
• Cooling that continues normally while the code shows

Possible causes

Listed in True's documentation

• The cable or connector between the control and display
• A loose plug from vibration or cleaning
• A mismatch between replaced parts
• The control board or the display

Other likely causes — what usually sits behind error code E13 on this control. A technician confirms which one it is before any part is replaced.

• A display cable pinched when the front panel was refitted
• Moisture in the connector from a washdown near the control
• A control and display from different revisions after an earlier repair

Safe checks before calling for service

How a technician diagnoses error code E13

1. Read the code and confirm the cabinet temperature with a thermometer.
2. Inspect the display cable and connectors for damage or moisture.
3. Reseat the connectors with power removed.
4. Compare the part numbers of the control and display for a mismatch.
5. Swap in a known good display or cable to isolate the failure.
6. Replace the board or display only after isolating it.

Technical reference

Document

Commercial Refrigeration General Control Guide TEC_TM_001 Rev C, Danfoss ETC p.88 Display Code Definitions

Edition

TEC_TM_001 | REV. C | EN, 09/3/2025, P#811072

Models / control

Danfoss ETC (current display)

Section

Electronic Control (with Display) - Display Code Definitions: Carel p. 74, Danfoss ERC/ETC p. 87, Dixell p. 96, LAE p. 110

Checked

October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.