Re: jeep australian 1997 xj sport
Could be a short in the data bus, or otherwise the PCM itself. Water or corrosion on pins inside connectors can short the PCI bus out. You could start measuring the voltage on pin 2 from the diagnostic juntion port connector, on the WJ it should be around 2V. When 0V, then the bus is shorted or the PCM is faulty. On the WJ, the PCM (and SKIM) can be disconnected from the data bus to see if the engine will run than. There is a special disconnect plug under the steering wheel area for that purpose on earlier WJ´s, maybe the XJ has it as well.