I have a JCB JS220LC excavator I am trying to run some diagnostics to figure out why the engine won't fire up. The engine is an Isuzu 4HK1 engine. Currently, the machine can start and run only if I turn the "limp mode" switch on. With the "limp mode" switch off, turning the ignition key cranks the engine, but the engine doesn't fire up. I read the service manual, and it describes the "limp mode" as an emergency mode operation, and the engine only runs at fixed RPM. The service manual also describes EMS, the LCD dash display; ECU1 (short for Engine Control Unit 1?), ECM (Engine Control Module?), and then ECUW, and ECW1. I looked at the electrical schematic, and it shows wiring/interconnections for EMS, ECU1, and ECM, but there is no ECUW nor ECW1 showing on the schematic. I would guess I don't have them, and the manual referred to those terms in general. In any case, what are an ECUW and ECW in a JCB machine or a JCB excavator?
Could it just have low coolant or something simple like that?
I certainly wish it’s something simple but coolant and engine oil levels are fine. I googled the ECUW, I was able to find a few results that seems relevant. But still no clue what ECUW stands for. https://www.ebay.com/itm/154215395981 https://maschinenprofi-24.de/JCB-332-L8465-JCB-HP-ECUW-332-L8465-JCB-HP-ECUW-BJ-2013