Unitended output activation

[bhughes7212]

Hello,

I am configuring an M150 with a JRR Evo x Paddleshift package. My simple bench setup consists of 12vdc and a spst switch to activate an external relay. This work fine until I go online with the ecu (PC is running windows 10 pro) at which time the ecu power relay activates and the switch has no effect! Disconnecting from the ecu, the switch and relay function is normal.

This is the only output that behaves in this manner.

I am at a loss...help.

[Stephen Dean]

Hi,

This is standard behaviour for the ECU Power Relay.

ECU Power Relay

This output can be used to hold power to the ECU after the ignition switch is turned off.

The output will remain on for 5 seconds after the engine stops, Coolant Pump After Run State is Disabled and M1 Tune is disconnected.

This system operates a switched output, typically to control a relay or other external power device.

The requested state of the output is reported by State.

For this system to operate the following requirements must be met:

Output Resource must be configured.
Drive must be configured.
Polarity must be configured if exposed.
Open Current must be configured if a Peak Hold Injector output is used.

[bhughes7212]

Hi Stephen,

I am aware of the power relay function. The issue was not being able to turn off the relay even after disconnecting from tune. The power pin (C26) was wired for continuous operation and not how I would wire the car.

In speaking with John Reed, seems my thinking around ecu "wakeup" was flawed. I have since installed a diode from the switch input to a power pin to provide "wakeup" and allowing the external relay (emulates OEM MFI relay) to provide full power. This eliminated the issue.

One more question...does battery backup actually do anything?

[Stephen Dean]

No.

[bhughes7212]

Thanks Stephen.