S60 ground issue

MarcusDH · Post by **MarcusDH** » Sun Sep 11, 2022 5:36 am

Hi, i have a problem with S60 ECU. The outputs for fuel pump relay, fan relay and shift light (pin 3, 4 and 6) are always grounded. When i switch ignition on the ecu sends one pulse to the fan relay (12v) but after that if you measure with a multimeter between + and pin 4 you have around 9v constant. Same in the pin 3 and 6. I check the harness and i tested the ECU out of the car with external power supply. Always same readings. You can see the shift light slightly on. The car runs perfect but suddenly and very random the ecu lose some sensor calibration (tps or crank sensor). I think this could be the problem. Thanks

Rob Stevens · Post by **Rob Stevens** » Sun Sep 11, 2022 6:05 am

What happens when you manually test with the PC connected via the test output facility.

MarcusDH · Post by **MarcusDH** » Sun Sep 11, 2022 6:42 am

Without activate the fan via pc i have 9.77v and when i activate via pc 12v (i remember you that i check the voltage between ecu positive and ground signal from pin 4) thanks

Rob Stevens · Post by **Rob Stevens** » Sun Sep 11, 2022 12:07 pm

??
No idea what you are doing or why.
Please try the test I suggested from the PC software.

If you are having problems with running use the data log facility to help trace the issue. In the diagnostic section there is a reset count that can help you identify loss of power to the ecu.

MarcusDH · Post by **MarcusDH** » Sun Sep 11, 2022 3:55 pm

Thanks for the reply.
If i test the fan or the shift light manually via PC they works fine. But if you turn ignition on the ecu sends one pulse to start the fan (in the life chart you can se a peak of 120-130ºC) and the shift light is on but like a dim light. I test the ecu with external power supply with the same results and if i check the voltage between pin 4 (fan relay) and positive i have around 9v (witch for me is grounded). The calibration fail occurs after around 50-70km and right now i cant test the car on the road. Thanks

stevieturbo · Post by **stevieturbo** » Sun Sep 11, 2022 4:17 pm

MarcusDH wrote: ↑Sun Sep 11, 2022 5:36 am Hi, i have a problem with S60 ECU. The outputs for fuel pump relay, fan relay and shift light (pin 3, 4 and 6) are always grounded. When i switch ignition on the ecu sends one pulse to the fan relay (12v) but after that if you measure with a multimeter between + and pin 4 you have around 9v constant. Same in the pin 3 and 6. I check the harness and i tested the ECU out of the car with external power supply. Always same readings. You can see the shift light slightly on. The car runs perfect but suddenly and very random the ecu lose some sensor calibration (tps or crank sensor). I think this could be the problem. Thanks

If your shift light is an LED, then it is quite common for it to glow a little.

How can you lose a crank sensor calibration ?

Post a datalog of whatever your problem is.

Are you saying your outputs are not working as installed in the vehicle to drive whatever it is they need to ? And the ecu does not send out 12v pulses.

Rob Stevens · Post by **Rob Stevens** » Mon Sep 12, 2022 3:47 am

Actually one of my cars does pulse the fan when I turn it on sometimes and has for years so I'd say it's a known problem

MarcusDH · Post by **MarcusDH** » Mon Sep 12, 2022 4:38 am

Thanks

MarcusDH · Post by **MarcusDH** » Tue Sep 20, 2022 1:38 am

Finally it seems that the problem was a spiked ECU. Thanks for the answers.

stevieturbo · Post by **stevieturbo** » Tue Sep 20, 2022 8:55 am

Spiked in what regard ?

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S60 ground issue

S60 ground issue

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