Radio and PCM - Modifications to Alarm Contact
Boxster5/98 9110/9112
Binder - 8/9, A/C & Electrics
Date: 12-15-98
Radio/PCM - Alarm Contact
Vehicle Type:
Boxster
Model Year:
As of 1997 (V)
Concern:
Modifications to the alarm contact for the radio and the Porsche Communication Management (PCM) unit.
Information:
If the alarm system is activated (armed), it will be triggered (the alarm sounds) when the contact on the radio (or PCM) bracket becomes grounded to the radio (or PCM) chassis; e.g. when the radio (or PCM) is moved from it's installed position. The radio contact circuit normally remains open by means of a Teflon insulating strip on the radio (or PCM unit). This strip prevents the contact lug from contacting the radio (or PCM) chassis until such time the radio (or PCM) is removed.
It is possible over time that the radio contact lug can wear through the insulating strip on the radio (or PCM). If this occurs, the alarm system will block the radio (or PCM) input signal when activating, thereby disabling radio (or PCM) removal detection.
Two (2) Teflon insulating strips (sourced locally) are now used in production (as opposed to a single one used previously), allowing for more resistance to wear.
Production change as of:
98 3WS 62 1390
98 2WU 62 4186
Fault Detection:
A radio (or PCM) contact malfunction can be detected by a double flashing of the light emitting diode (LED) of the alarm system, in conjunction with a single beep from the alarm horn after locking the doors. Presence of these indicators may indicate a grounded radio (or PCM) contact, and can be verified with the PST2:
- Using the PST2, select "Alarm System", and then "Activation State of Memory". If the following message is displayed, it may indicate a grounded connection at the radio contact.
Radio contact
Type of activation: secured via radio (or secured via lock)
- This can also be checked in the "Input signals" menu with the PST2. Select "Radio contact" under "Input signals" of the "Alarm system" with the PST2.
If the contact is open, (no ground connection), the contact is O.K.
If the contact is closed, (ground connection) there is most likely a problem with the radio contact.
Note:
The PCM has two (2) alarm contacts, one at the main PCM unit, and the other at the CD-ROM disk drive. However, these two (2) contacts cannot be differentiated with the PST2 tester. The alarm control unit detects these as a single input. Therefore these two contacts must be diagnosed individually (isolated) in the event of a contact problem.
Parts Info.:
Part Number Description
Teflon Tape Sourced Locally
996 645 106 00 Radio Plate Contact Lug
Work Procedure:
When addressing radio contact concerns on vehicles produced prior to the above mentioned VIN's, it is recommended to retrofit the vehicle with two (2) Teflon strips as outlined below:
- Remove radio (or PCM) from the mounting bracket.
- Mark the position of the existing Teflon strip on the radio (or PCM). Remove the Teflon strip.
- Affix a new Teflon strip (cut to the proper size) at the marked location. Affix a second strip over the first one.
- Reinstall the radio (or PCM)
Note:
Perform this operation at the PCM CD-ROM disk drive contact as well, if so equipped.
- Erase any existing faults, and/or events in the "Activation State Memory" of the alarm system using the PST2.
- Check for the reoccurrence of the radio contact fault message (in the "Activation State of Memory"). If the radio contact problem still exists, it is possible that the Teflon strips are incorrectly positioned. Correct the installed position of the Teflon strips as necessary.
- Enter radio or PCM security codes if necessary.
Labor:
Labor Operation Time Unit Description
91 20 41 OO 40 TU Removing/installing two new insulating strips on the radio
9110 41 00 70 TU Removing/installing two new insulating strips on the PCM
Includes:
Removing and installing radio or PCM unit, reading and erasing fault memory.
Literature:
Boxster Technical Manual, Binder - Group 0, Diagnosis, page 0-D3.
Also see: Diagnosis/Troubleshooting, Alarm System, page 90-D1.