Alarm Code 10
Out of serviceHigh Discharge Pressure
Thermo King · reefer alarm · OEM code 10 · Thermo King
Protect the load now
Refrigerant discharge pressure hit the safety limit. The unit protects itself by shutting down — which means the clock on your load has already started. Check airflow through the condenser first.
CoolingTODO(verify): confirm whether this alarm is configured as a check-level or shutdown-level alarm on the specific controller and unit. On many configurations the unit shuts down to protect the compressor, which means box temperature starts climbing immediately.
LoadThe truck is fine — the load is not. If the unit has shut down, box temperature is rising from this moment, and how long you have depends entirely on what is in the trailer, how it was pre-cooled, and the ambient temperature. Check the condenser at the next safe stop and call a reefer service line before you decide to keep rolling.
Typical repair cost
- Parts
- $1,115–$4,050
- Labor
- 0.5–5 hr × $125–$210/hr = $63–$1,050
Provisional figures — pending verification against our receipt dataset.
Labor rate: provisional national placeholder — TODO(verify), not yet from our collected dataset. How we build these ranges.
Need it fixed
Phone-verified shops, with the date we last called each one.
What Alarm Code 10 means
This is a transport refrigeration unit alarm, not an engine fault code. It is reported by the reefer controller and has nothing to do with the tractor's engine ECM. The tractor may be perfectly healthy while the box is losing temperature.
Common causes
- Condenser coil blocked with road film, insects, or debrisThe first thing to check and frequently the whole answer. It is also the one fix a driver can do at a truck stop.
- Condenser fan not turning, turning slowly, or turning backwards after a repair
- Refrigerant overcharge
- Non-condensables (air or moisture) in the system after an improper service
- Condenser inlet or outlet valve restricted, or a stuck three-way valve
- Very high ambient temperature combined with a marginal condenser
- High pressure cutout switch or discharge pressure transducer failed
No frequency data yet. We have fewer than 5 verified repair receipts for Alarm Code 10, so we are not going to print percentages. Causes above are listed in no particular order. Had this fixed? Tell us what it turned out to be.
Technician note pending
A credentialed technician annotation for Alarm Code 10 has not been commissioned yet. Until it is, this page stays a draft and is excluded from our sitemap. We do not publish invented first-hand experience. How we verify content.
How a technician diagnoses it
- 1
Look at the condenser before anything else. Road grime, plastic bags, and insect load are visible from three feet away and are the most common cause.
- 2
Confirm the condenser fan runs and pulls or pushes air in the correct direction. A fan spinning the wrong way after a motor replacement produces this alarm consistently.
- 3
Check for anything parked or stacked against the unit blocking airflow. A trailer nosed up against a wall in summer will do this.
- 4
Read discharge pressure on the controller and compare against a gauge set at the service port. That settles transducer-versus-real.
Tool: Refrigeration gauge manifold · Spec: TODO(verify): high pressure cutout setpoint per unit model
- 5
Note the ambient temperature and the box setpoint. A unit that only alarms in the afternoon heat on a deep-frozen setpoint is being asked for more than it has.
- 6
If the coil is clean and the fan is right, the system needs a refrigeration technician with gauges to assess charge and non-condensables. Do not vent or add refrigerant to chase a pressure alarm.
Spec: TODO(verify): manufacturer charge specification by unit model
- 7
Log the alarm, the ambient temperature, and the box temperature at the time it set before clearing. That record is what tells a claims adjuster whether the load was ever out of range.
Parts and labour
| Part | Part number | Parts cost |
|---|---|---|
| Condenser coil cleaning (service) | TODO(verify) | $75–$250provisional |
| Condenser fan motor | TODO(verify) | $250–$900provisional |
| High pressure cutout switch / discharge transducer | TODO(verify) | $90–$400provisional |
| Condenser coil assembly | TODO(verify) | $700–$2,500provisional |
| Labour | 0.5–5 hr | $63–$1,050 |
Labour priced at provisional national placeholder — TODO(verify), not yet from our collected dataset. How we build these numbers.
Can I keep running the load?
The truck is fine — the load is not. If the unit has shut down, box temperature is rising from this moment, and how long you have depends entirely on what is in the trailer, how it was pre-cooled, and the ambient temperature. Check the condenser at the next safe stop and call a reefer service line before you decide to keep rolling.
TODO(verify): confirm whether this alarm is configured as a check-level or shutdown-level alarm on the specific controller and unit. On many configurations the unit shuts down to protect the compressor, which means box temperature starts climbing immediately.
Find a shop that handles this
We call every shop before it appears here, and publish the date.
Sample records only — seeded to demonstrate the directory. None of these numbers has been called.
Phoenix, AZ · 24/7 · mobile service
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Dallas, TX · 24/7 · mobile service
Codes that usually show up with this one
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