Tyre Pressure monitoring fault 01521

4.2 V8 32v Naturally Aspirated - 414 bhp
Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Tyre Pressure monitoring fault 01521

Post by Heardy » Sun Sep 09, 2018 9:59 pm

Hi all
Having recently bought a 2007 Rs4 i'm just on with a few jobs one of which is the tyre pressure monitoring system
One of the sensors was missing from one wheel which I have now replaced, all other sensors are working as this has been confirmed by testing them with an after market universal tyre pressure monitoring receiver and programmer
The tyre pressure system had been coded out of the dash (I have now reprogrammed it using VCDS), when read for faults it just has -
01521 Sensor for tyre pressure
004 - no signal/communication -MIL ON
I have tried the reset procedure numerous times but no good

One slightly odd thing I've noticed is that there's no live data in the measuring blocks for tyre pressures it just has the specified pressures which doesn't seem right

Has anyone got any ideas to rectify this ?

Jason
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Mon May 06, 2019 9:14 pm

Has anyone any ideas with this ?
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

coffey555
5th Gear
Posts: 1137
Joined: Wed Aug 17, 2011 2:41 pm

Re: Tyre Pressure monitoring fault 01521

Post by coffey555 » Mon May 06, 2019 9:20 pm

Could be the aerial which is located behind the rear bumper. Fake plastic grill just pops out and the aerial is on the right hand side.

Could also be the controller which is located in the side panel in the boot behind the passenger side rear seat.

If you have access to a Vagcom I think it tells you if it is an aerial fault.

Are the sensors the correct type for the car? If they use a different frequency they will not be detected.
Misano Red RS4 B7 Avant

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Mon May 06, 2019 9:58 pm

There’s only that fault code stored nothing else relating to aerials etc, there is some live data on the aerial which fluctuates, so i presume its fine
I cam only check the frequency of the sensors if i whip the wheels off pop the tyres off and have a look, which I could so
Any explanation as to why there’s no live data in measuring blocks ?
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

coffey555
5th Gear
Posts: 1137
Joined: Wed Aug 17, 2011 2:41 pm

Re: Tyre Pressure monitoring fault 01521

Post by coffey555 » Mon May 06, 2019 10:40 pm

The only time I had no values in the measuring blocks was when my sensors died.

Before I disabled the warning I changed my aerial, then my controller module.

Disabled the alarm for years before fitting new sensors a couple of years ago when I had the wheels refurbed.

Went through the tyre change procedure (as they were new sensors) and the system has worked as normal ever since.

If you are not getting any values then the car must not be seeing the sensors. The sensors can go into sleep mode if left sitting too long. Letting all the air out before reinflating wakes them up again (so the batteries don't drain when sitting on the warehouse shelf).

You might also need to drive the car for up to 10 mins to ensure the sensors are active. Been years since I messed about with them but there should be a few good threads on here about it.

So either the sensors are faulty or they are the wrong frequency.

Do you know any local RS4 owners with working sensors? You could try parking next to them to see if you can read their wheels?
Misano Red RS4 B7 Avant

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Tue May 07, 2019 6:21 am

I’m pretty sure the antenna on the car is okay (well functioning at least) as the live data suggests
The transponders in the wheels are definitely transmitting as i have access to an aftermarket tyre transponder programmer and their defiantly alive

I have tried waking them by letting them down and also driving it but to no avail

There’s a thought i do know someone with a B7 cabriolet i’ll have a look and compare it to that one and see if there any anomalies

Thanks again coffey555
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

coffey555
5th Gear
Posts: 1137
Joined: Wed Aug 17, 2011 2:41 pm

Re: Tyre Pressure monitoring fault 01521

Post by coffey555 » Tue May 07, 2019 2:31 pm

No problem, hope you manage to fix it.

You can always switch it off again.....
Misano Red RS4 B7 Avant

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Tue May 07, 2019 7:21 pm

coffey555 wrote:
Tue May 07, 2019 2:31 pm
No problem, hope you manage to fix it.

You can always switch it off again.....
Yeah i know, I’m just a stickler for things working, ive asked on rosstech forum for ideas or what to do next
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Mon May 13, 2019 6:49 am

I’ve had another good look this weekend and the module can definitely see the transponders as you can see it pick them up in live data (in the part that shows the last transponder to be seen) i just don't know why it wont take the 2 new id’s
In the procedure below i did all that but it’s not very specific about weather to go into the dis and press reset
I have tried it though

“Matching a New Sensor
If a new sensor was installed it must be matched to the module.
Turn the Key on with a battery charger connected.
Wake up all sensors as previously described immediately followed by correcting the tire pressure.
Leave the Key On for an additional 20 minutes and do not move the vehicle. This will allow the module to learn the ID from the new sensor.
After the learning procedure has been performed, take the vehicle for a test drive. The length of the drive may vary depending on the vehicle but 5 to 8 minutes is typically sufficient.
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Sun May 19, 2019 7:08 am

Just to update you, I disconnected the tpms module for a few hours, reconnected it tried the usual reset initially (which didn’t work) so instead tried the wheel change option and bingo, went back into the menu and reset as normal and no more warning light

I decided to re check the live data and its accepted both new id’s from the sensors
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

coffey555
5th Gear
Posts: 1137
Joined: Wed Aug 17, 2011 2:41 pm

Re: Tyre Pressure monitoring fault 01521

Post by coffey555 » Mon May 20, 2019 2:20 pm

Haha, bloody things! Good effort for sticking with it and getting it working again.
Misano Red RS4 B7 Avant

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Tue May 21, 2019 4:23 pm

coffey555 wrote:
Mon May 20, 2019 2:20 pm
Haha, bloody things! Good effort for sticking with it and getting it working again.
👍🏻 I wasn’t going to be beaten !!
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

glscholes
Neutral
Posts: 8
Joined: Sat Sep 28, 2019 4:53 pm

Re: Tyre Pressure monitoring fault 01521

Post by glscholes » Sat Oct 05, 2019 4:34 pm

Hi, first time.posting here, and I am having a problem with the 2007 RS4 B7 I have bought. Love the car (why wouldn't you) but the tpms system has been coded out of the instrument cluster, which is not a problem, I can enable that as I have VCDS. What I need to know is how to view the live data, do you need to enable security access to view, and if so, what is the security access code? Looking at the sensor id's, it looks like the same numer comes up in 3 of the 4 wheel positions, which is obviosly wrong, so I want to try a wheel swop, but don't know how to do this either! Any help would be greatly appreciated to get my system working properly again. Thanks in advance, Graham

Heardy
2nd Gear
Posts: 157
Joined: Tue Apr 29, 2008 4:19 am

Re: Tyre Pressure monitoring fault 01521

Post by Heardy » Sat Nov 16, 2019 9:16 am

Just to further update this post incase anyone has the same issue. The disconnecting of the module then relearn did work for sometime but subsequently it was a failure. The module accepted the id’s but again same code flagging 01521
I ended up buying a replacement module off ebay, fitted it
relearned and all good 100% fixed. The module must have had an internal fault !

Hi Graham
Sorry only just read your post as I don’t cone on here that often.
To view live data you go to measuring blocks which by the sound of it your already there (security access isn’t needed)
You correct about the id’s they should be different, unsure why they should be the same. If you were to replace any of the sensor as i did with mine it should learn the new sensor id
If you do a wheel swap you’ll either need to code the tpms out or fit 4 transponder valves to the wheels that your going to fit
Hope thats some help
Jason
2007 B7 RS4
Previously
C5 RS6 Saloon Avus, Phase 2 Viper Remap, Wagners, Full Milltek, Hotchkis Arb's, 390mm C6 Brake's, H&R Coilovers

highrise
1st Gear
Posts: 66
Joined: Mon Sep 13, 2021 11:00 am

Re: Tyre Pressure monitoring fault 01521

Post by highrise » Sun May 29, 2022 9:53 pm

Hi Heardy,

I appreciate this is a pretty old thread but your issues seems to be the same as I'm facing.

I've replaced all tyre sensors.
Replaced antenna.
Replaced the module.

I'm still getting the 01521 error.

I'm really not sure what else could be the issue?

One thing I have found is that when you select wheel change, it kills the error in the dash (yellow flat tyre with cross) for 20min. I think this is the relearn period. This has led me to believe I've fixed at each stage only the return!

I'm using OBDEleven and cannot see any live data from the sensors. Module is present as is the antenna.

I know I can just code it out but it's driving me mad that I can't fix it.

Any help appreciated.

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