QuestionI most recently replaced the battery in my 1999 S80 T6. Once I replaced the battery the power locks stopped working but everything else is fine. How do I fix this?
AnswerRashida,
There has been many problems with locks on car like yours. The start would be to have the dealer or a Volvo shop look at the car. Maybe a simple reprograming will work. Here is more info...
1999 Volvo S80 2.9 L6-2.9L VIN 97 B6304S3
Vehicle Level Accessories and Optional Equipment Keyless Entry Technical Service Bulletins Antitheft/Keyless Entry - Door Lock Logic
Antitheft/Keyless Entry - Door Lock Logic
Notes
NO: 83-25
DATE: 7-31-2002
MODEL: 2001- S60, V70, V70 XC, 1999- S80
CHASSIS: All
SUBJECT: Door Lock Logic
REFERENCE: VADIS
THIS TECH-NET NOTE SUPERCEDES PREVIOUS TNN 83-25 DATED 1/28/2002
Update includes remedy if lock is incorrectly adjusted under the heading "Mechanical/Electrical Activation"
DESCRIPTION:
In an electrical system with distributed functionality, such as the ones found in the vehicles above, it can sometimes be difficult to find faults related to central locking. Replacement of the CEM or PDM/DDM does most often not solve strange central locking behavior issues.
This Tech Net Note is intended to assist in general door lock fault tracing and to provide an understanding of how the door lock logic is intended to function in order to avoid misdiagnosis. Design and function information for central locking will be in Vadis A 2002. Guided fault tracing can also be found by using symptom entry in Vadis. Some additional information is located in design & function for the CEM in Vadis F 2001.
The following is generally applicable to the US version of locks, referred to as the two-step unlocking system. Note that customers may have one step unlocking which has different characteristics. Among them is the function that all locks unlock at once, but also that the doors cannot be locked with the door switch if the door is open.
Locks, as mentioned below, refer to both the driver side and passenger side doors, not the trunk or fuel lid.
SIGNAL FLOW:
Generally speaking, the signal flow in the vehicle depends on which way the doors are locked or unlocked:
Via remote: The lock or unlock signal goes from remote fob to the UEM that processes the input and sends a CAN message to the GEM, containing information about what button has been pressed. The GEM then sends out a lock or unlock command based upon which button was pressed. The lock/unlock command is carried out by the DDM/PDM/REM respectively.
*Note : The lock or unlock command is not dependant upon the status of the door locks.
Via mechanical key: If the key is turned clockwise, the DDM detects this as a request for lock and sends this signal to the GEM. The GEM then sends out a lock command, which is carried out by the DDM/PDM/REM respectively. If the key is turned counter-clockwise the same signal flow is valid but instead the command will be an unlock command. Note that, for the driver door, the lock will operate by the mechanical linkage and is independent of the signal flow.
*Note : The lock or unlock command is not dependant upon the status of the door locks.
Via DDM or PDM (with two step unlocking): If the door switch is pressed, a signal is sent from DDM/PDM to the GEM with information that the door switch was pressed. The GEM reaction will depend on the current lock status. If any door is open the result will be a lock command. If all doors are locked it will result in an unlock command, which is carried out by the DDM/PDM/REM respectively.
*Note : This function will not operate as described above if the key is in the ignition. This is to prevent the accidental locking of keys in the vehicle.
MECHANICAL/ELECTRICAL ACTIVATION:
The lock system is a combination of mechanical and electrical activation. In order to operate the door locks in the correct way, the GEM needs to know the status of the locks so that it can decide whether to lock or unlock when the switch in the driver or passenger door is pushed.
The wire carrying the status of the door lock (locked or unlocked) is shown in the wiring diagram as "DL" and is connected to the DDM for the driver door, PDM for the passenger door and the GEM for the rear doors.
As a consequence, the lock motor will always follow a mechanically changed status so that it has the correct position for a subsequent command.
This can be seen by slowly moving a doorknob from unlocked to locked. In the middle of the sequence the doorknob will be pulled down by the motor. If the knob is pushed down quickly, the door will lock and shortly thereafter the motor can be heard acknowledging the new status.
When a doorknob is pulled up, the status of this signal changes to "unlocked" and the motor follows to this new position. When the knob is pushed down the status changes to "locked" and the motor follows to this new position.
Cases have been reported with self-unlocking vehicles and other similar symptoms; e.g. not all doors lock when locking the vehicle. This can be explained by a door lock switch giving the wrong status, e.g. a locked door with knob down may get a "DL" signal stating "unlocked". The motor will then follow the status and actually unlock the vehicle.
In cases like this, the correct remedy is to replace the lock.
Self-locking can occur in combination with code OO1A if the lock mechanism is wrongly adjusted. Remedy for this fault is to verify and adjust the mechanism.
VEHICLE COMMUNICATION:
Visual feedback on the lock behavior can be viewed either through VADIS or by breakout box. In VADIS, through vehicle communication, the following signals can be monitored:
-status of the key position
-status of the driver's door (open or closed)
-status of the passenger door (open or closed)
-status of the left rear door (open or closed)
-status of the right rear door (open or closed)
-status of the tailgate (open or closed)
-status of the lock switch for the left rear door
-status of the lock switch for the right rear door
*Note : The open/closed door status read from the GEM is interesting to view as an overall functionality check of the lock. However, functionality wise it is mostly affecting a one-step unlocking system.
*Note : The key position has a significant impact on remote fob and mechanical key operation. If the ignition switch is faulty, giving the faulty status that key is still in ignition, the DDM and PDM will operate the central locking but the remote or mechanical key will not.
