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ecu hold power and speed issue


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I m a pro tuner in Belgium, I installed a few Link ECUs on customer cars and love this thing. Now I installed one on our demo car (Skyline R32 GTR), it is the plugin version G4+.

First issue, ECU hold power :

Ecu was fine at first, then i upgraded firmware to activate knock control. I few minutes of parameters check after, i began to have strange ecu ON-OFF behaviour, whithout touching the ign switch.

I figured out it was the ECCS relays that were switching all the time. I bypassed them and car started ok. Now i plugged back the relays normaly and no more switching, but ecu stays ON as soon as I plug the battery, So the ECU switch the ECCS relay as soon as it is plugged to the battery, dispite IGN switch being ON or OFF. 

This creates bad engine stops as engine is staling because only fuel pump is of. 

Is it maybe firmware issue or probably hardware issue ?


Second issue :

About vehicule speed. The value constantly move from a value and its double. So for exemple I m at 50kmh, I read a value constantly switching between 50 and 100. I played with the input parameters but not a lot to play with and same result. Is there a way to include a filter on this input ?



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For the ECU hold power problem, a couple of things to check. The Ignition switch signal comes into the ECU on pin 45, it then activates the ECCS relay output (driving low), which comes out of the ECU on pin 16. The ECCS relay then powers up providing pins 49 and 59 with power. This then powers up the top-board of the ECU. You can check what is happening on these pins to diagnose the fault. In PCLink go to ECU Settings > Aux Outputs > ECU Hold Power, and make sure the Keep Alive time is set to 0.00s.

For your speed input issue. Have a look at the Digital Inputs tab of the Runtime value Window (F12 key to open). You will be able to see the frequency coming in on digital input 3. Is this nice and stable (when your speed is stable!) or is it jumping around? If it is jumping around then there is a problem with the signal coming into the ECU.


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Check the voltage to pin 45 to make sure this is 0V with key off and 12V with key on.

The out put to the ECCS relay pin 16 should only be at ground when there is 12V on pin 45.

If it is at ground all the time it indicates the mosfet in the ECU has failed or there is a short on the pin.  

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I checked and yes pin 16 is always at ground. +12v on pin45 or not.

seems mosfet dead as you said. It could explain the strange behaviour i had at the time when pin16 was continuously switching.

can i replace this mosfet myself ? I run a chiptuning company so i have equipement to do this. Can you give me a picture of it and the ref of the mosfet ?


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