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Navigation: Wiring information

Power hold relay

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Power hold is a function to let the ECU be powered even after ignition key has been turned off, to for example control engine fans or other functions needed when engine is turned off under a certain amount of time.

Note: Only low driving outputs (GPO/INJ) can be used for the power hold output function.

 

 

MaxxECU MINI/STREET/SPORT/V1/RACE/PRO

(MaxxECU PRO has some nice features built-in, scroll down if you have a PRO)

 

 

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Diodes (type: 1N4004G)

70-003-18 (elfa.se)

641-1311-1-ND (digikey.com)

 

 

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1. Configure output, Output --> Output config, set ECU power hold relay on the wired output.

 

 

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2. Configure input, Inputs --> Digital inputs, configure input as Ignition key.

 

 

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3. Configure the power hold function, Outputs --> Power hold, configure to suit your need, see more examples below.

 

 

 

MaxxECU PRO

Note: MaxxECU PRO has diodes built-in on KEY IN 12V input (K3) on third CMC connector so no need for external diodes.

 

 

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1. Configure output, Output --> Output config, set ECU power hold relay on the wired output.

 

 

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2. Configure input, Inputs --> Digital inputs, configure input as Ignition key.

Note: MaxxECU PRO has a special input (KEY IN 12V) with built-in diodes.

 

 

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3. Configure the power hold function, Outputs --> Power hold, configure to suit your need, see more examples below.

 

 

 

Examples

 

Using a fixed power hold time

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When the digital input Ignition key is deactivated, the engine is immediately stopped by fuel / ign cut, but the Power hold relay is held active for an additional time (Additional ECU power hold duration) to finish homing idle stepper motors, running cooling fans etc. When the time expires the power hold relay is released and the power to the ECU is cut.

 

 

Different power hold times from a table

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By using the power hold duration from a table instead of a fixed value, more options will be available. Even 4D can be enabled on this table...