# MKR NB1500: can't turn off modem

**URL:** <https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955>\
**Category:** MKR NB 1500\
**Created:** [July 1, 2025, 2:51pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955 "2025-07-01T14:51:53Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![tipo1000](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/tipo1000/32/1013044_2.png) [@tipo1000](https://forum.arduino.cc/u/tipo1000)\
**Post date:** [July 1, 2025, 2:51pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/1 "2025-07-01T14:51:53Z")

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I'm trying turn off the modem to save current.

Measuring with Power Profiler II the whole board takes 64mA. Trying to turn off the modem with AT+CPWROFF current goes down to 56mA, so only 8mA reduction. Looks like AT+CPWROFF has some effect but doesn't really turn off modem.

I have out of box firmware in SARA: L0.0.00.00.05.06,A.02.01.

Can it be the reason that fw is old? And where do I get newer fw?

Thanks...

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**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\
**Post date:** [July 1, 2025, 3:34pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/2 "2025-07-01T15:34:26Z")

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I suggest to consult the [modem data sheet](https://cdn.prod.website-files.com/66db0a16ec359c496fe320da/684c3e6f8337cda0394b8a52_SARA-R4%20data%20sheet.pdf) to see what power options are available, how they are selected and what current is consumed in the default state of the modem.

Also, since you are measuring current consumption of the entire board, what currents do each of the other devices normally consume?

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**Author:** ![tipo1000](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/tipo1000/32/1013044_2.png) [@tipo1000](https://forum.arduino.cc/u/tipo1000)\
**Post date:** [July 1, 2025, 4:15pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/3 "2025-07-01T16:15:30Z")

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AT+CPWROFF is the command to power-off modem, according to data sheet.  
All other parts on board together take max 30mA (excluding modem). So it has to mean modem is not off when board consumes 56mA.

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**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\
**Post date:** [July 1, 2025, 4:30pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/4 "2025-07-01T16:30:12Z")

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Take the issue up with U-blox. They have a user forum.

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<div class="post-metadata">

**Author:** ![tipo1000](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/tipo1000/32/1013044_2.png) [@tipo1000](https://forum.arduino.cc/u/tipo1000)\
**Post date:** [July 3, 2025, 12:37pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/5 "2025-07-03T12:37:46Z")

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I'm not sure what was wrong but now it works.

Also, I was able to cut PCB trace betwwen SARA power input (+3V8) and C31 and hookedup PP II in between. In power off state current consumption is 8uA.

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**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [December 30, 2025, 12:38pm UTC](https://forum.arduino.cc/t/mkr-nb1500-cant-turn-off-modem/1392955/6 "2025-12-30T12:38:02Z")

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