Automatic Compression Release
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Cruiser
Joined: Aug 2009
Posts: 126
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From: Maryland
Automatic Compression Release
2007 SG with 110
How can you test to see if your ACR is working. I am getting the following code 1655 ACR LO. I checked power back to the fuse and that is OK.
How can you test to see if your ACR is working. I am getting the following code 1655 ACR LO. I checked power back to the fuse and that is OK.
Grand HDF Member
Joined: Nov 2009
Posts: 4,315
Likes: 1,663
From: Tampa
The only thing I can think of is on a HOT motor:
pull the spark plug leads, hit starter, listen to how "labored" the starter sounds
then pull ACR fuse and do that again. If they're working the starter should sound a LOT more labored when the ACR's are not working.
pull the spark plug leads, hit starter, listen to how "labored" the starter sounds
then pull ACR fuse and do that again. If they're working the starter should sound a LOT more labored when the ACR's are not working.
A compression test with and without the fuse (or disconnected from the fuse) will also tell.
The ACR could be bad/electrically open and that is why the code is being generated.
Last edited by Ed Ramberger; Mar 23, 2019 at 09:34 PM.
not so sure about that.
Road Master
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Grand HDF Member
Joined: Nov 2009
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From: Tampa
Color me skeptical about this. It seems pretty technologically advanced for an ECM to know when the cranking is on the compression stroke, especially considering cranking isn't registering RPM so the ECM would have a consistent reference point to know when to trigger the ACR like it does spark. Not to mention, different battery levels of performance regarding how fast it can crank an engine over.
The ACR is on while the start button is pressed, but if I recall correctly it's not directly wired to that circuit. I'm pretty sure there's an ECM output for it. Why that's the case is beyond me, just seems like unnecessary load on the ECM if you ask me. Mine's wired to the output side of the starter solenoid so when the starter motor has power, so do my ACR's.
The ACR is on while the start button is pressed, but if I recall correctly it's not directly wired to that circuit. I'm pretty sure there's an ECM output for it. Why that's the case is beyond me, just seems like unnecessary load on the ECM if you ask me. Mine's wired to the output side of the starter solenoid so when the starter motor has power, so do my ACR's.
Color me skeptical about this. It seems pretty technologically advanced for an ECM to know when the cranking is on the compression stroke, especially considering cranking isn't registering RPM so the ECM would have a consistent reference point to know when to trigger the ACR like it does spark. Not to mention, different battery levels of performance regarding how fast it can crank an engine over.
The ACR is on while the start button is pressed, but if I recall correctly it's not directly wired to that circuit. I'm pretty sure there's an ECM output for it. Why that's the case is beyond me, just seems like unnecessary load on the ECM if you ask me. Mine's wired to the output side of the starter solenoid so when the starter motor has power, so do my ACR's.
The ACR is on while the start button is pressed, but if I recall correctly it's not directly wired to that circuit. I'm pretty sure there's an ECM output for it. Why that's the case is beyond me, just seems like unnecessary load on the ECM if you ask me. Mine's wired to the output side of the starter solenoid so when the starter motor has power, so do my ACR's.