Hi fellows i got the alarm code popped up. Do you guys have any idea about what causes this? I can’t clear this alarm and i have a load right now its on -5 degrees. Is it dangerous to drive like that? Because i just picked up the load and will deliver it tomorrow. Do i need to drop the load back and go to the mechanic asap?
Thermo King S-600 HELP ASAP!!!
Discussion in 'Refrigerated Trucking Forum' started by hendrix69, Oct 21, 2025.
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Last edited: Oct 21, 2025
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As I know, the 603 code means the unit thinks something is wrong with the exhaust. It could be a dirty filter, a sensor acting up, or a blockage somewhere. The 42 code is the unit protecting itself, so it drops into low power to avoid damage. That is why it is not running full strength.
You are not in immediate danger. The reefer will still keep your load cold, just not as strongly as usual. For a short haul it should be fine, but you want to watch the temperature. If it starts climbing, that is when you need to act.
Do not panic, but do not ignore it either. Have a certified Thermo King mechanic check it before your next long run or in very cold weather to make sure your load stays safe. -
Go into the hidden menu and you can clear it.
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The mechanic cleaned whole intake system with egr but the alarm codes still showed up, and he said i need to go to the dealer to clear ECU alarms because my trailer is doesn’t allow to clear the alarms he said. you guys any other advice?
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Mechanic tried to do that but it doesn’t allow to clear the alarms in hidden menu
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Then he doesn't know what he's doing.
Or the previous owner had a security code. -
Are u talking about maintenance access or guard access? He tried the clear the alarm in both menu in front of me. It doesn’t allow to clear them. And he said your trailer has no ecu clear option in the menu. If you know how to go there can you help me to do that?
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Easier to u-tube guarded access than to try and explain on here.
https://www.youtube.com/shorts/EsHXDlUjVY0
If it has a code to get in you will have to go to a dealer and have them remove it.hendrix69 Thanks this. -
I just went to the thermo king dealer they checked the ecu clear in my screen and they said my software is too old previous owner never touched and didn’t the software update since 2015. Thats why the ecu clear section is not showing in the screen. And needs to be get update it. Then will be able to see clearly why the alarm code is not gone they said.
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I just went to the thermo king dealer they checked the ecu clear in my screen and they said my software is too old previous owner never touched and didn’t the software update since 2015. Thats why the ecu clear section is not showing in the screen. And needs to be get it update.Then will be able to see clearly why the alarm code is not gone they said.
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