How to tell if MDS is on or off

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RCFiddyOne

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I don't see what the block has to do with anything? It should just be all top end and electrical items.

You couldn't be more wrong. Below are pictures from the Engine and Performance Warehouse manual on rebuilding the '03 and up 5.7L HEMI engine.

MDS is oil pressure driven. That is why you don't go in the 4 cylinder mode during idle - not enough oil pressure for the solenoids. ECO light on the dash and MDS are not related.
 

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boblonben

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to add to this, when im in ECO in low speeds, the exhaust has a 4cylinder drone to it. also when u manualy shift (arrow up or down) or put it into tow haul the ECO will shut off no matter what rpm you are at. I think the ECO is the MDS. thats my opinion
you are correct.
 

boblonben

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You couldn't be more wrong. Below are pictures from the Engine and Performance Warehouse manual on rebuilding the '03 and up 5.7L HEMI engine.

MDS is oil pressure driven. That is why you don't go in the 4 cylinder mode during idle - not enough oil pressure for the solenoids. ECO light on the dash and MDS are not related.
rong, the ECO light and MDS are related. BUT, there are two other situations where the ECO light will come on with the MDS still not engaged.
 

indept

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The ECO light is not a gaurantee that MDS is on but if MDS is on then the eco light will be on from what I've seen.
That said, there are 3 indicators that MDS is on
1. Sound
2. Sound
And last but not least:
3. Sound
 
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