True Refrigerator Error Code hi / Lo: LAE Temperature Alarms
On a True cabinet with an LAE control, hi and Lo are the high and low temperature alarms. The cabinet keeps running, so the alarm is your warning to check the load and the box. Silence it, close the door, and measure the temperature with a thermometer.
Medium: product can warm or freeze if the alarm persists, but the cabinet is running.
- Code
- Hi / Lo
- Maker
- True
- Equipment
- Reach-in refrigerators
- Applies to
- LAE control
What does True error code Hi / Lo mean?
The LAE control shows hi or Lo when the cabinet air goes outside its limits, as on the T-49-HC. On the GDM/T Scientific line the limits are 45 F and above for hi and 36 F and below for Lo; refrigerators use the settings on the control. A door-open alarm follows after 60 seconds, and it stops when the door is shut. The cabinet keeps running, so the alarm tells you to look at the load and the box, not that the cabinet has stopped. Hi usually means heat is trapped or not leaving: a leaking gasket, a dirty condenser or an iced evaporator. Lo can come from a set point or limit that was changed. A thermometer in the product settles whether the food is safe, and a service call settles why the limit was crossed.
Affected models and control systems
True cabinets with an LAE control, such as the T-49-HC; limits of 45 F and 36 F apply to the GDM/T Scientific line.
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
- Hi or Lo on the display
- Alarm tone
- Door alarm after 60 seconds
- Cabinet noticeably warm or cold
Possible causes
Listed in True's documentation
- A door left open or a leaking gasket on the LAE cabinet
- A dirty condenser coil that raises cabinet air above the hi limit
- An iced evaporator coil on the LAE cabinet that blocks cold air
- Alarm limits or the set point changed on the LAE control
Other likely causes — what usually sits behind error code Hi / Lo on this control. A technician confirms which one it is before any part is replaced.
- A hot pan loaded into a cabinet that cannot pull it down quickly
- A freezer-like set point entered by mistake on the keypad
- A door switch stuck so the door alarm never ends
Safe checks before calling for service
- Press any button to silence the alarm.
- Close the door; the door alarm stops when the door is shut.
- Check the temperature with a thermometer and move product if it is out of range.
- Clear dust from the area around the condenser.
- If the alarm returns, tell us whether it was hi or Lo.
How a technician diagnoses error code Hi / Lo
- Read which alarm is active.
- Check the temperature with a calibrated thermometer.
- Review set point and alarm limits.
- Check door seal, condenser and evaporator condition.
- Test the main probe against a reference.
- Correct the cause before changing limits.
- Condenser and fan work is behind panels with live wiring.
- Limits and set point are controller settings that must match the product.
- An iced coil needs a controlled defrost, not scraping.
How error code Hi / Lo differs from similar codes
On the GDM/T Scientific line the limits are fixed numbers, while standard refrigerators use the control's settings.
Technical reference
- Document
- GDM/T-SCI Installation Manual TEC_TM_288, Temperature Alarms
- Edition
- TEC_TM_288 | REV. A | EN, 10/23/2024, P#889161
- Models / control
- LAE control
- Section
- Electronic Temperature Control - LAE Display Codes, p. 26
- 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.
Related True reach-in refrigerator error codes
What temperatures trigger hi and Lo?
On the GDM/T Scientific line, 45 F and above for hi and 36 F and below for Lo. Refrigerators use the control's settings.
Is the cabinet stopped?
No, it keeps running.
What is the 60-second alarm?
A door-open alarm that sounds after 60 seconds and stops when the door shuts.
Need help with True error code Hi / Lo?
A technician confirms the cause on site and gives you the price in writing before any work starts.