Key Fob Will Not Unlock the Doors - keywords alarm deterrent door lock PZM remote RFA RKE theft transmitter unlock

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

The driver would find that upon approaching their locked vehicle that the key fob would not unlock the doors. They would have to manually unlock their door with the key. When they get in and start the car theft deterrent system will be set off. The driver may also experience a flashing IPC or hear the control power relay cycling.

This issue is two fold:

First, the IPC was not waking up upon receiving class 2 serial data, as it should have been. If the IPC or radio do not wake up upon receiving class 2 serial data or the driver commands it through the DIC, the PZM is specified to go into storage mode within 20 minutes instead of 23 hours as it normally would.

Second, when the version of PZM in this vehicle is in storage mode a software bug will cause the PZM to create the symptoms described above. This mode occurs if the vehicle is entered before 23 hours have elapsed since the vehicle was left by the driver, but after the real time clock of the PZM has passed midnight.

First, determine if the driver commanded storage mode through the DIC. If so, replacing the PZM with part number 09378190 (Fixed software) or later will correct the condition. Next, if the condition is not driver commanded, the message monitor should be used as described in the attached procedure to determine if the IPC or radio is not waking up upon receiving class 2 serial data. The malfunctioning IPC or radio should be replaced. If the malfunctioning component can not be determined, the PZM should be replaced with the updated one mentioned above. However, in this case, the customer may notice that the away presets in the radio will be lost in 20 minutes from parking the vehicle instead of 23 hours, as it would normally take.

Use this procedure to test for PZM lockup due to PZM going into storage mode prematurely. The customer symptoms will be that the key fobs will not work and when the vehicle is started it will go into theft mode if the vehicle had been locked prior to entry.

Turn on the Tech 2 message monitor. Go into diagnostics then circuit check and then class 2 message monitor.

Key the ignition to run for one minute or longer.

Turn key off and remove key from ignition and open and close the door.

Do not open any doors or activate any switches or key fobs or anything that would wake up the electrical system.

Wait four minutes from closing the door and locate the message monitor lines from the radio and IPC. Message monitor line consists of module name, whether active or inactive, and active/inactive counter. Record the active/inactive counter value for both the radio and IPC.

Wait an additional twenty minutes and record the monitor values for both the radio and IPC.

If the value of either the radio or IPC have not increased by at least four, replace that component.

Check PZM part number. If not part number 09378190 (Current production as of 6/15/99) or later version, replace PZM with the latest version.

Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.