2014 Hino 338 a few issues

dirtyhands

New Recruit
Mechanic
Hello, I hear there's. Hino guru in this joint.

I have a 2014 Hino 338

Driver complains of low coolant level alarm, trans over temp alarm and abs alarm. I cant reproduces these alarms, and I'm told they are intermittent with a key off/on temporarily fixing whatever the issue is.

Coolant level is max in reservoir and radiator, (all new coolant when I replaced block heater last month, bled system of all air.

Hoses to and from reservoir seem to be in good condition with no blockages,

Caps are in good condition.

I feel like the abs lamp and the trans hot are related, not too familiar with Hino trucks as 99% of our fleet is international. But I do believe if abs is acting up, can cause trans not to shift into OD causing fluid to overheat.

I am not certified yet so I will not touch brake assemblies for liability reasons. But my boss is too cheap to send it to Hino for diagnosis.

Side note, truck was fine with 0 issues until we sent it to Hino for new leaf springs 2 months ago, been having these issues since we picked it up.

Any ideas would be appreciated. Cant seem to find much online
 
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coalminer

Veteran Expediter
Retired Expediter
When the ABS is in fault mode, the torque converter will not lock up which will overheat the transmission, so those 2 are for sure related. If the rpms are higher that normal because there is no lock up it may cause the low coolant alarm but not totally sure on that one.

Im not sure on the 2014s but check to see if there is an ABS diagnostic button under the dash by the diagnostic connector, if so when you push it will flash codes through the ABS light. One easy thing to check is the air gap on the ABS sensors, I bet one of them is a little too far away, probably one of the rear ones since it all started when they changed the leaf springs. Also trace the wires to make sure they were not nicked when the springs were changed.
 

greasytshirt

Moderator
Staff member
Mechanic
Coalminer is exactly right. I'd like to add that the low coolant level alarm is probably not related. There are plenty of reasons why the low coolant alarm can go off. Here are some examples.
They are prone to leak at hose connections when it's cold. Especially the hose clamp on the coolant outlet neck.
They can leak coolant from the oil cooler. Sometimes externally from the head gasket.
They can suck atmospheric air past the water pump seals, putting bubbles in the coolant that interfere with coolant returning back to the radiator from the overflow tank.
Head gasket/injector cups can leak combustion gases into the coolant, with the same effect.
The tube attached to the bottom of the overflow bottle sometimes falls off, making coolant return impossible.
And rarely, the water level sensor fails.
 
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