Raspberry pi 5 active cooler fan full speed all time

[wkg21]

Describe the bug

I updated my raspberry pi 5 eeprom to:

root@pineberry:/boot/firmware/overlays# rpi-eeprom-update -a BOOTLOADER: up to date CURRENT: Wed 22 Jan 00:16:51 UTC 2025 (1737505011) LATEST: Wed 22 Jan 00:16:51 UTC 2025 (1737505011) RELEASE: default (/usr/lib/firmware/raspberrypi/bootloader-2712/default) Use raspi-config to change the release.

and after update fan connected to built-in 4-pin JST-SH PWM fan connector. started working on full speed despite low temperature:

vcgencmd measure_temp

temp=26.8'C

and is not obeying settings in /boot/firmware/config.txt

dtparam=fan_temp0=45000 dtparam=fan_temp0_hyst=5000 dtparam=fan_temp0_speed=75

dtparam=fan_temp1=50000 dtparam=fan_temp1_hyst=5000 dtparam=fan_temp1_speed=128

dtparam=fan_temp2=55000 dtparam=fan_temp2_hyst=9000 dtparam=fan_temp2_speed=192

dtparam=fan_temp3=60000 dtparam=fan_temp3_hyst=9000 dtparam=fan_temp3_speed=255

found solution this need to be added to config.txt

dtparam=cooling_fan=on

so behavior changed with a new firmware when you compare what is in README.

less /boot/overlays/README cooling_fan Enables the Pi 5 cooling fan (enabled automatically by the firmware)

so looks like that not enabled automatically now.

Steps to reproduce the behaviour

1. have a fan connected to built-in 4-pin JST-SH PWM fan connector
2. update epprom to CURRENT: Wed 22 Jan 00:16:51 UTC 2025 (1737505011) I was on september 2024 before

Device (s)

Raspberry Pi 5

Bootloader configuration.

rpi-eeprom-update

BOOTLOADER: up to date CURRENT: Wed 22 Jan 00:16:51 UTC 2025 (1737505011) LATEST: Wed 22 Jan 00:16:51 UTC 2025 (1737505011) RELEASE: default (/usr/lib/firmware/raspberrypi/bootloader-2712/default) Use raspi-config to change the release.

System

cat /etc/rpi-issue

Raspberry Pi reference 2024-11-19 Generated using pi-gen, https://github.com/RPi-Distro/pi-gen, 891df1e21ed2b6099a2e6a13e26c91dea44b34d4, stage2

vcgencmd bootloader_version

2025/01/22 00:16:51 version a77530632346c8ac1d579fa3c369f9980401e821 (release) timestamp 1737505011 update-time 1738681359 capabilities 0x0000007f

vcgencmd version

2025/01/22 00:16:51 Copyright (c) 2012 Broadcom version a7753063 (release) (embedded)

uname -a

Linux pineberry 6.6.74+rpt-rpi-2712 #1 SMP PREEMPT Debian 1:6.6.74-1+rpt1 (2025-01-27) aarch64 GNU/Linux

Bootloader logs

No response

USB boot

No response

NVMe boot

No response

Network (TFTP boot)

No response

[pelwell]

Using that EEPROMversion the cooling fan is working as expected for me, with or without your dtparams, and without explicitly loading the cooling-fan overlay.

1. Where are you reading the temperature? I recommend cat /sys/class/hwmon/hwmon0/temp1_input.
2. If I unplug the fan, reboot the Pi, then plug it back in again, I get the behaviour you do. Running sudo dtparam cooling_fan fixes it. I guess that works for you as well?
3. How are you booting the Pi - SD card, or something else?

During reboot, do you see the fan twitch at all before it starts running at full speed? The firmware is supposed to let the fan spin a bit so that activity on the FAN_TACH line indicates the presence of a fan. Newer versions of the EEPROM then turn off the fan until the kernel starts, whereas it used to be left on.

[wkg21]

Ad.1 i'm using "vcgencmd measure_temp" to get temperature Ad.2 yes i unplugged fan and plugged back and issiue persisted until i added : dtparam cooling_fan and after that fan control started working. Ad.3 using nvme

without dtparam cooling_fan when rebooting fan was at full speed, stopped for a while and again went full speed. also when powering on it was stopped at the beginning and after a while went full speed and stayed like that.

now with "dtparam cooling_fan on" fan is not running during boot and after. it only starts when cpu goes in my case over 45 degress.

i believe /boot/overlays/README should be updated:

cooling_fan Enables the Pi 5 cooling fan (enabled automatically by the firmware)

[pelwell]

When the fan is spinning, what does cat /sys/class/hwmon/*/fan1_input show?

[pelwell]

And no, the README doesn't need updating - that is how it works for me, and it is how it should also work for you.

[wkg21]

!. fan runs at full speed.

grep fan /boot/firmware/config.txt # dtparam=cooling_fan=on

cat /sys/class/hwmon//fan1_input cat: '/sys/class/hwmon//fan1_input': No such file or directory

2. fan runs only when temp higher than my 45 degrees

root@pineberry:~# grep cooling /boot/firmware/config.txt dtparam=cooling_fan=on

root@pineberry:~# vcgencmd measure_temp ; cat /sys/class/hwmon/*/fan1_input temp=37.8'C 0

running # stress -c 24 root@pineberry:~# vcgencmd measure_temp ; cat /sys/class/hwmon/*/fan1_input temp=45.5'C 1789

[wkg21]

And no, the README doesn't need updating - that is how it works for me, and it is how it should also work for you.

unfortunately it doesn't for me. BTW mine is fresh install with "Raspberry Pi Imager" and "Raspberry Pi OS Lite 64bit"

[ivi-lab]

I have the exact same issue after updating to the latest version (1737505011) from an old version (1731427844).

I've tested this with a clean Pi OS install with no edits (e.g config.txt). Here are some closer observations:

At startup the fan now pulses twice at 100%. No real issue, just an observation from the previous one pulse it used to do.

Only after a soft reboot does the fan continuously run at 100%. If a soft/hard shutdown is performed and then powered up, the fan speed behaves fine. Also to note there is no fan pulse after a soft reboot, it just continuously runs at 100%.

[pelwell]

Is that exactly the same? I read @wkg21's report as the fan no longer working as expected, whereas yours is clearly saying that boot is OK, but reboot is not. For what it's worth, both cases work for me with the current EEPROM image.

[ivi-lab]

@pelwell Exactly the same as his initial report although he was previously on a different eeprom version. In both cases the fan speed runs at 100% even when the temp is low. This only started after the latest eeprom update.

@wkg21 I'm curious what M.2 HAT are you using?

Maybe this has something to do with additional hardware (a HAT). I have a PoE M.2 HAT sitting on mine. My test results were all while connected to PoE. There's no difference whether booting from a M.2 or SD card. What I haven't tried is removing the HAT. I'll report back soon.

[ivi-lab]

So I removed my HAT and used an official Pi 5 power supply. It made no difference, the fan speed issue is still the same.

I also did the test on a second RPi 5 8GB with the same results.

[wkg21]

I have removed nvme and did fresh install on sdcard and have exactly the same behavior. fan speed 100% all the time without dtparam=cooling_fan=on and normal behavior after adding i that setting to config.txt.

for nvme i'm using pineboard bottom version.

[ivi-lab]

@wkg21 How does the fan behave when you shut it down (not reboot) and turn it back on?

[wkg21]

when i poweroff without cooling_fan option in config. rpi shuts down as expected and when powering it on by pressing power button, fan is off for ~8s and then it goes full speed.

[timg236]

The latest (default) bootloader 2025-05-08 has the following which should correct probe failures with the RPi case-fan or the RPi active cooler. https://github.com/raspberrypi/rpi-eeprom/commit/17a9f162c940caf24592b466f59a9df24b9409df

@wkg21 Please can you verify if this works for you?

[jasonbrianrivero]

@timg236 Hello! I also experience that the raspberry pi active cooler runs even if the temperature is around 49-51 degrees. Is there any workaround? My bootloader is currently up to date as per "sudo rpi-eeprom-update -a

[pelwell]

That is expected - the threshold is 50C, with a 5C hysteresis which means that the fan won't switch off until the temperature drops below 45C.

You can control the temperatures using the following dtparam settings:

        fan_temp0               Temperature threshold (in millicelcius) for
                                1st cooling level (default 50000). Pi5 only.
        fan_temp0_hyst          Temperature hysteresis (in millicelcius) for
                                1st cooling level (default 5000). Pi5 only.
        fan_temp0_speed         Fan PWM setting for 1st cooling level (0-255,
                                default 75). Pi5 only.
        fan_temp1               Temperature threshold (in millicelcius) for
                                2nd cooling level (default 60000). Pi5 only.
        fan_temp1_hyst          Temperature hysteresis (in millicelcius) for
                                2nd cooling level (default 5000). Pi5 only.
        fan_temp1_speed         Fan PWM setting for 2nd cooling level (0-255,
                                default 125). Pi5 only.
        fan_temp2               Temperature threshold (in millicelcius) for
                                3rd cooling level (default 67500). Pi5 only.
        fan_temp2_hyst          Temperature hysteresis (in millicelcius) for
                                3rd cooling level (default 5000). Pi5 only.
        fan_temp2_speed         Fan PWM setting for 3rd cooling level (0-255,
                                default 175). Pi5 only.
        fan_temp3               Temperature threshold (in millicelcius) for
                                4th cooling level (default 75000). Pi5 only.
        fan_temp3_hyst          Temperature hysteresis (in millicelcius) for
                                4th cooling level (default 5000). Pi5 only.
        fan_temp3_speed         Fan PWM setting for 4th cooling level (0-255,
                                default 250). Pi5 only.

To increase the temperature at which the fan comes on to 55C, put the following in config.txt:

dtparam=fan_temp0=55000

[jasonbrianrivero]

That is expected - the threshold is 50C, with a 5C hysteresis which means that the fan won't switch off until the temperature drops below 45C.

You can control the temperatures using the following dtparam settings:

        fan_temp0               Temperature threshold (in millicelcius) for
                                1st cooling level (default 50000). Pi5 only.
        fan_temp0_hyst          Temperature hysteresis (in millicelcius) for
                                1st cooling level (default 5000). Pi5 only.
        fan_temp0_speed         Fan PWM setting for 1st cooling level (0-255,
                                default 75). Pi5 only.
        fan_temp1               Temperature threshold (in millicelcius) for
                                2nd cooling level (default 60000). Pi5 only.
        fan_temp1_hyst          Temperature hysteresis (in millicelcius) for
                                2nd cooling level (default 5000). Pi5 only.
        fan_temp1_speed         Fan PWM setting for 2nd cooling level (0-255,
                                default 125). Pi5 only.
        fan_temp2               Temperature threshold (in millicelcius) for
                                3rd cooling level (default 67500). Pi5 only.
        fan_temp2_hyst          Temperature hysteresis (in millicelcius) for
                                3rd cooling level (default 5000). Pi5 only.
        fan_temp2_speed         Fan PWM setting for 3rd cooling level (0-255,
                                default 175). Pi5 only.
        fan_temp3               Temperature threshold (in millicelcius) for
                                4th cooling level (default 75000). Pi5 only.
        fan_temp3_hyst          Temperature hysteresis (in millicelcius) for
                                4th cooling level (default 5000). Pi5 only.
        fan_temp3_speed         Fan PWM setting for 4th cooling level (0-255,
                                default 250). Pi5 only.

To increase the temperature at which the fan comes on to 55C, put the following in config.txt:

dtparam=fan_temp0=55000

Thanks for this one, it now works!

[KelvinHu]

This is probably not related, but are third-party active coolers be auto-detected by the firmware? I have a Waveshare Active Cooler B for the RPi 5 and it necessitates dtparam=cooling_fan=on when plugged into the fan header.

EDIT: without dtparam=cooling_fan=on running sensors from lm-sensors doesn't show a pwmfan-isa-0000.

[timg236]

The auto-detection works by driving the fan-PWM low (max-speed) and observing fan-tach so third party fans should work if they use the same signals.

[pelwell]

@KelvinHu The auto-detection has changed/improved in more recent firmwares. What is your EEPROM version (vcgencmd bootloader_version)?

[KelvinHu]

@KelvinHu The auto-detection has changed/improved in more recent firmwares. What is your EEPROM version (vcgencmd bootloader_version)?

2025/07/17 17:25:12
version a668b6e6edce3274de221324b93cb8741e4a7f7c (release)
timestamp 1752769512
update-time 1754979517
capabilities 0x0000007f

Here is my /boot/firmware/config.txt as well if it's relevant:

[pi5]
# Automatically load initramfs files, if found
auto_initramfs=1

# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d,cma-512
# max_framebuffers=2

# Don't have the firmware create an initial video= setting in cmdline.txt.
# Use the kernel's default instead.
disable_fw_kms_setup=1

# Run as fast as firmware / board allows
arm_boost=1

# Set PCIe slot to gen three
dtparam=pciex1_gen=3

# Explicity enable active cooler fan header
dtparam=cooling_fan=on

# Fan Threshold 0 - 40 degrees
dtparam=fan_temp0=40000
dtparam=fan_temp0_hyst=35000
dtparam=fan_temp0_speed=63

# Fan Threshold 1 - 50 degrees
dtparam=fan_temp1=50000
dtparam=fan_temp1_hyst=45000
dtparam=fan_temp1_speed=127

# Fan Threshold 2 - 60 degrees
dtparam=fan_temp2=60000
dtparam=fan_temp2_hyst=55000
dtparam=fan_temp2_speed=191

# Fan Threshold 3 - 70 degrees
dtparam=fan_temp3=70000
dtparam=fan_temp3_hyst=65000
dtparam=fan_temp3_speed=255

# Setup ethernet over USB-C port
dtoverlay=dwc2

EDIT: I also don't know if this is emblematic of a bigger problem (or being out of date) but checking /sys/devices/platform/cooling_fan/hwmon/hwmon2/fan1_input gives a result of 0 while the fan is audibly loud and while pwm1 shows 255.

[timg236]

The fan auto-detection logging was improved a while ago and issues around some fan designs which cannot be auto-detected are now well understood. Closing.