Tire Monitor System - Warning Lamp ON/DTC 01521
44 08 122011237/3
November 5, 2008
Vehicle Information
44 DTC 01521 stored in the Tire Pressure Monitoring System (TPMS)
Condition
TPMS warning displayed in the instrument cluster and DTC 01521 stored in the TPMS control unit.
Technical Background
In some vehicles below the specified VIN range the TPMS antenna may be installed upside down or the mounting bracket may have detached from the roof causing the antenna to have poor reception. If the antenna is not facing in the proper direction it will not always receive signals from all 4 sensors and DTC 01521 "Tire pressure sensor lower specified value too low" maybe stored. Keep in mind the spare tire sensor is never learned and is not monitored.
Production Solution
A new antenna-mounting bracket was introduced for vehicles built after VIN 4F_6N065000.
Service
Use the following steps for diagnosis:
1. Remove the rear interior light assembly and inspect how the TPMS antenna is mounted.
a. If the antenna is mounted between 2 pieces of foam then check if it is facing in the correct direction. Without removing the foam, check if two cutouts at one end of the antenna are facing up towards the roof of the vehicle (see illustration).
b. If the two cut outs are not facing towards the roof of the vehicle, then mount the antenna using the new bracket part number 4F0 907 526. Make sure that the lettering on the antenna is facing the interior of the vehicle.
c. If the antenna is facing in the right direction then it is not necessary to remove the foam for the antenna to function properly. But if the foam is damaged and/or cannot support the antenna properly it should be removed and the antenna should be mounted using the new bracket part number 4F0 907 526.
d. If the antenna is mounted in a plastic bracket, which was originally attached to the roof of the vehicle but now has detached from the roof, then install the new bracket part number 4F0 907 526.
2. After any antenna installation issues have been resolved, reinstall the rear interior light assembly.
3. Now perform the "Initialize wheels" procedure.
4. After the "Initialize wheels" procedure is finished, check the first 4 digits in MVB 17 for the System Status. When the system has learned all 4 sensors and their pressures the System Status should be 0049. Below are some of the possible system statuses:
- 0049 The tire pressure monitoring has been adapted successfully.
- 0149 The tire pressure monitoring system is in the adaptation phase. The road test was probably aborted too early. The adaptation procedure must be repeated.
- 0249 The tire pressure monitoring system cannot be adapted. The specified pressures of the tires are not OK. Correct specified pressures, save them and then repeat the adaptation procedure.
If the antenna is properly mounted and is facing in the proper direction then follow GFF test plan for the DTC.
Warranty
Required Parts and Tools
Additional Information
More information on this system can be found in the following resources:
- Owners Manual
- ElsaWeb
- SSP: 993403
- VAS Scan Tool
All part and service references provided in this TSB are subject to change and/or removal. Always check with your Parts Dept. and service manuals for the latest information.