MHI truck refrigeration unit

**phil Landon** · 29-03-2012, 01:59 AM

Hi there Guys, i was wondering if anyone can help, have a mid 1990's MHI unit on a truck. It was working a year ago according to the owner. He went ot switch it on and now it is showing DP5 on the dispaly. It is on R404A, not sure of the model numbers as it has been painted over.

Can anyone help with the fault code list as it really hard to get anything off the MHI site

Any help would be very much appreciated

thanks

**Robert Hilton** · 30-03-2012, 09:32 PM

DPS, dual pressure switch.
I assume it's a direct drive unit TDJ 300 or 430 maybe?
Are the electrics integral in the unit?
If it is a direct drive then either the DPS is u/s or there is too little refrigerant
Let me know which unit it is and I'll get back to you

**Zizo** · 04-06-2012, 09:52 AM

Hi,
we have a similar problem.
Direct drive unit TDJ 300 DL is not working.
The controller lights alarm lamp and showing code rd5 (or possible rdS).
We have checked the pressure (5bar) and the pressure sensor.
Neither service in our town does not know fault codes for this model.

**Robert Hilton** · 05-06-2012, 07:36 PM

A quick scan of the MHI defects for TDJ/TNW/TU units with old style controller

dP5 = DPS (dual Pressure Switch) High cutout 30 bar High cut in 24 bar

Low cutout 2 bar Low cut in 2.3 bar
FU1 = F1
FU2 = F2
FU3 = F3
rd5 = TD (discharge temperature sensor) Liquid inject @ 125 celcius Cutout @ 135 celcius Cut in @ 100 celcius

**Zizo** · 06-06-2012, 10:43 AM

Thank you very much Robert!
We will try to check this sensor and general state of charger.
I suppose this sensor is usual copper thermal resistance.

**Robert Hilton** · 06-06-2012, 10:02 PM

It is an NTC sensor. It also tells me you have either a Sanden or Seltec compressor. Mitsubishi own compressors are not fitted with a discharge temp sensor.

**Zizo** · 07-06-2012, 08:39 PM

Today my brother (the owner) said that idea to mechanics. Yes, it's TDS as you wrote!
Mechanics did not know about the existence of this sensor in this type of compressor (and did not notice it!).
My brother asked me to convey to you his gratitude!

I don't know about manufacturer of this compressor, I'm not an specialist in this area 8-)
But if I understood correctly the speech of my brother - there are two (or more) types of this Mitsubishi systems. First - has not this sensor and have controller v.1. Second (this) - has v.2 controller (labeled on cover) and use this TDS. When this broken TDS was disconnected system starts normally.
Tomorrow he will try to change this sensor to similar from more modern compressor.

And thank you for information about several possible manufacturers. Brother want to change the seals on compressor and asked me for search for partnumbers. So, it will complicate the search for seal set, I think.
How can I determine the manufacturer? It should have some labels on body?

P.S.
This truck is real japanese Frankenstein!
It is ISUZU, but has NISSAN diesel engine, transmission from MAZDA and refrigeration unit from MITSUBISHI.
Neither Isuzu nor Nissan has no electric schemes for them in catalogs.

**Robert Hilton** · 08-06-2012, 05:21 AM

Sanden and Seltec compressors are fitted when there is too little space for a normal Mitsubishi item.
There should be a label on the compressor somewhere on the compressor. If you could find a gasket set, and if it is wise to strip and rebuild it is another matter. A replacement comptressor is a better option. If you do have it replaced then a new oil seperator would be advised. MHI does advise you to replace the seperator every 2 years.

**Zizo** · 08-06-2012, 06:51 AM

It's clear. I also think that the replacement compressor is better. The owner should think about it.

Mechanics did not notice the sensor because they suppose Mitsubishi manufacturer and did not expect that sensor existance. Now TDS was changed to similar from other compressor. OK

But after few hours upper hose from cooling radiator bursts and antifreeze poured to compressor. The coupling of the compressor started to smoke. And now we have error code FU2. So, I think it's first steep for buying of new compressor.

Robert can you write more detailed description of FU2 code?
Thank you very much for your advices.