Originally Posted by red_2005_convertible

Hi Mike,
when you say antenna, do you mean the pickup ring that goes around the ignition. If you take the C3 connector off the SKREEM and measure the resistance between pins 1 and 2, they should be connected, and probably measure less than 100 ohms (manual is a little confusing since it talks about cavity 1 to cavity 2, which I think means on the SKREEM because otherwise why turn the ignition on?). Also, are there any DTC error codes? It sounds like the antenna ring might be bad. There are cheap devices for sale that can tell you if the antenna is emitting a signal.
-Jerry


Diagnostic Test (page 8Q-41)
1. MEASURE THE RESISTANCE OF THE SENTRY KEY ANTENNA CIRCUIT
Disconnect the Sentry Key Antenna Ring connector from the
SKREEM.
Turn the ignition on.
Measure the resistance of the Sentry Key Antenna circuit from cavity 1
to cavity 2 of the connector.
Is the resistance between 4 and 6 ohms?
Yes >> Replace the Sentry Key Remote Entry Module.
Perform SENTRY KEY VERIFICATION TEST.
No >> Replace the Sentry Key Antenna Ring assembly.
Perform SENTRY KEY VERIFICATION TEST.

From the manual:
The Sentry Key Remote Entry Module (SKREEM) has the following functions: receiving and evaluating the Radio
Frequency (RF) keyless entry remote signal, actuation of door locks in conjunction with the Central Locking Pump/
Security System Module, and enabling the vehicle theft security alarm with confirmation via the turn signals. When
the RKE transmitter is operated, an RF signal is transmitted. If the SKREEM recognizes the RF signal as valid, it
actuates the Central Locking Pump/Security System Module through the Body Control Module. The vehicle is then
locked or unlocked through the power locks system. Connected to the SKREEM is a Sentry Key Antenna Ring
which surrounds the ignition lock cylinder. When the ignition is switched on, the Sentry Key Antenna Ring is supplied
with power. A data block is transmitted inductively via the Sentry Key Antenna Ring to the SKREEM and then
on to the Powertrain Control Module. If the antenna ring data block content is invalid or if vehicle battery power is
too low to build up enough power for the antenna ring, the Powertrain Control Module will not receive the proper
signal. This is displayed with the message “Start Error” in the Instrument Cluster.
The SKREEM contains an RF transceiver and a microprocessor. The SKREEM transmits RF signals to and receives
RF signals from the ignition key transponder through a tuned Sentry Key Antenna Ring that is wired to the
SKREEM. If the Sentry Key Antenna Ring is not mounted properly around the ignition lock cylinder housing, communication
problems between the SKREEM and the ignition key may arise. These communication problems will
result in ignition key transponder-related faults. The SKREEM also communicates over the Controller Area Network
(CAN) data bus with the Powertrain Control Module (PCM), the Instrument Cluster, the Body Control Module (BCM),
and/or the DRB IIIT scan tool.