ISM Fault
06-29-2018, 03:32 PM
#1
Member
Thread Starter
ISM Fault
Hi.
Was driving my GL550 2011 on the interstate the other day and suddenly when pressing the accelerator, the car would not change gears and also rev at high rpms without shifting. Recently, both front and rear speed sensors were replaced with genuine parts. No check engine light came on. Afterwards, car was scanned and came up with code 1709: "The actuator motor in the component A80 ISM (Intelligent Servo Module) for Direct Select cannot reach its specified target position."
Has anyone had this problem? Is the ISM faulty or the Valve body/conductor plate? Where is the ISM located and how much does the stealership cost to change it?
Thanks
Tek
Was driving my GL550 2011 on the interstate the other day and suddenly when pressing the accelerator, the car would not change gears and also rev at high rpms without shifting. Recently, both front and rear speed sensors were replaced with genuine parts. No check engine light came on. Afterwards, car was scanned and came up with code 1709: "The actuator motor in the component A80 ISM (Intelligent Servo Module) for Direct Select cannot reach its specified target position."
Has anyone had this problem? Is the ISM faulty or the Valve body/conductor plate? Where is the ISM located and how much does the stealership cost to change it?
Thanks
Tek
07-01-2018, 09:31 PM
#4
Out Of Control!!
A80 control module is located on the outside of passenger side of the transmission and to remove is a major job--drive shaft removal, transmission bracket removal and loads of bl bla's see WIS doc AR2719P0550GZA---its a major job and I suspect labor and parts 2500
07-07-2018, 01:36 AM
#5
Super Member
The ISM is bolted to the driver's side of the transmission case. I don't think this codes is what's causing your transmission to stay in one gear. What are you scanning with? You need to scan with Xentry/DAS.
07-07-2018, 05:13 AM
#6
Member
Thread Starter
Hi I am currently scanning with Aurelius Maximus and have the code 1709.
02-01-2023, 05:00 AM
#7
Hi.
Was driving my GL550 2011 on the interstate the other day and suddenly when pressing the accelerator, the car would not change gears and also rev at high rpms without shifting. Recently, both front and rear speed sensors were replaced with genuine parts. No check engine light came on. Afterwards, car was scanned and came up with code 1709: "The actuator motor in the component A80 ISM (Intelligent Servo Module) for Direct Select cannot reach its specified target position."
Has anyone had this problem? Is the ISM faulty or the Valve body/conductor plate? Where is the ISM located and how much does the stealership cost to change it?
Thanks
Tek
Was driving my GL550 2011 on the interstate the other day and suddenly when pressing the accelerator, the car would not change gears and also rev at high rpms without shifting. Recently, both front and rear speed sensors were replaced with genuine parts. No check engine light came on. Afterwards, car was scanned and came up with code 1709: "The actuator motor in the component A80 ISM (Intelligent Servo Module) for Direct Select cannot reach its specified target position."
Has anyone had this problem? Is the ISM faulty or the Valve body/conductor plate? Where is the ISM located and how much does the stealership cost to change it?
Thanks
Tek
please update your solution. Thank you
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02-01-2023, 05:25 AM
#8
MBWorld Fanatic!
The usual valve body/conductor plate failure mode is a red “drive to workshop” warning and then the transmission locks in 2nd gear.
That is if you slow down enough for it to do that - if you stay at highway speed I do believe it holds highway gear until you slow down but will not upshift again.
That is if you slow down enough for it to do that - if you stay at highway speed I do believe it holds highway gear until you slow down but will not upshift again.
02-01-2023, 09:54 AM
#9
Thank you for your inputs.
Mine is running at low/high speed great. Only problem when weather is cold, dashboard lights go off and red msg drive to workshop …
tried to test ISM actuation test and red “drive to workshop….” Popped right ip on dashboard…
still searching and tracing for stray current, modules. …
Mine is running at low/high speed great. Only problem when weather is cold, dashboard lights go off and red msg drive to workshop …
tried to test ISM actuation test and red “drive to workshop….” Popped right ip on dashboard…
still searching and tracing for stray current, modules. …
Last edited by EmilyMB; 02-01-2023 at 10:03 AM.
