CAT 320D2 ECM seem not working

[borcom]

Hi people, I am having an issue with a 320D2 (Serial Nº PFE10094). The machine was working 3 weeks ago with no issue and yesterday it didn´t start. Not even crank. The display turns on with the key, but there is no info (like fuel, temperatures, etc). We tried disconnecting the ECU (part Nº 386-3444) and it is the same. There are no codes also in the dash, like there is no comunication with the ECU. In one corner of the ECU, there is a red led blinking when the ignition is on.

We tried to start the engine bridging (idk if it is the corret word) the starter motor and the engine cranks well and even start for a few seconds.

All fuses are ok, and we tried switching places of the relays and didn´t change anything.

We measure with multimeter the red wires in the connector of that ECU and there are 24v and Ground.

I test some sensors for 5v but none of them have steady 5v, some have some come-and-go 3.5, 0.8 and so.

I have a 320DL (Serial Nº A8F00985), I am not sure if the ECUs are the same and I can test switching them. I don´t want to burn another ECU if they are not compatible.

If anyone have any information it will be very appreciate.

 

[Nige]

Has any welding been done on the machine recently.?

Check your message inbox. I will send you an electrical schematic so that you know what you are testing. The 5v sensor signal wires will generally not show 5v, especially if they are the PWM type. In that case you will require a multimeter capable of measuring duty cycle to check sensor output.

I have a 320DL (Serial Nº A8F00985), I am not sure if the ECUs are the same and I can test switching them. I don´t want to burn another ECU if they are not compatible.

The Machine ECM for machine Serial Number A8F00985 is not the same Part Number as the machine with the fault. I would not recommend switching the ECMs even for a limited test.

It may be necessary to connect Cat ET to the machine in order to make a full diagnosis.

 

[borcom]

Hello Nige, I just came from the machine. No, there has been no welding in that machine. A few weeks ago, there was a thunderstorm near, maybe I am very unlucky.

I checked the machine with the electric schematic you send me, there is 24v in + pins both of Machine and Engine ECMs. I also check and there is 24v in the +Key Pin of both ecus.

I connected the ET but I can only see the monitor system.

I didn´t check sensor outputs, but I am starting to be more sure that maybe it is a ECU problem.

Is there a way to test if the ECUs are working?

 

[Nige]

Is there a way to test if the ECUs are working?

Not really. If ET will not communicate with a particular ECM there is a possibility that re-flashing the software will bring it back to life, but it’s not guaranteed. That process will require a dealer version of ET.