raffa54 Posted May 5 Report Share Posted May 5 Im suddenly having weird issue where DI 3 which Im using for the ignition signal for the ECU hold power setup with my PDM seems to randomly work. The ECU will power up but once its on the DI will only deactivate randomly and turn off the Aux to the PDM. I've confirm the 12v is switching on and off at the ECU pin, and all Aux's except for the one for ECU hold power have been physically disconnected so theres nothing backfeeding. This has been working fine in the past, but I did accidently short the live terminal at the alternator earlier in the week working in the area, really hoping I havent cooked the ECU. Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 5 Report Share Posted May 5 Measure the voltage on the DI pin in reference to one of the main ground pins such as A34 in both the on and off condition, possibly it is not crossing the thresholds. Also, it's hard to understand your wiring from your description so a sketch of how it is wired would help. What are you using the ECU hold power function for? Quote Link to comment Share on other sites More sharing options...
raffa54 Posted May 6 Author Report Share Posted May 6 12.4V with the ignition on and 0.02V with it off to both plug A GND's The standard setup for the car was for the cooling fans and turbo coolant pump to run on after the engine is stopped, I was hoping to retain that. Hold power time is set to 0.1s atm as I havent set any of that up yet. Excuse my crappy drawing. Ignition signal comes from the main relay for the car, supply for the ECU/CAN and all other solenoids etc comes from the PDM. There is no longer anything else being supplied by the main/fuel relays. Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 6 Report Share Posted May 6 How are you confirming it is the DI that is causing it to not shut down? Are you saying the DI status in PC Link still shows active when the issue occurs? And when the issue occurs with it showing active, you have measured 0V on the DI Pin at the same time? The DI pull-up is off? Quote Link to comment Share on other sites More sharing options...
raffa54 Posted May 6 Author Report Share Posted May 6 Good point, I tested at the plug between the relay and DI3 and I still had voltage on the ECU side with the ignition off. The Diode has failed and I wasnt seeing it with Plug A disconnected because Aux 8 was powering down the PDM when unplugged. Quote Link to comment Share on other sites More sharing options...
raffa54 Posted May 6 Author Report Share Posted May 6 Diode replaced and it's all working again, I've teed it off the main harness with a 2 pin plug so it's at least serviceable if it fails again. @Adamw is it just a matter of setting an arbitrary time for the hold time and turning off the Aux once a temp set point is reached for the fan and pump control? I've only seen people setting hold power up for stepper motor control so far. Quote Link to comment Share on other sites More sharing options...
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