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Home >> Cadillac >> 2007 >> STS Base, 3.6 7, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Anti-Theft Systems >> Keyless Entry System And Remote Functions >> Diagnostic Information and Procedures >> Key Fob Not Detected
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Key Fob Not Detected

Key Fob Not Detected

Step Action Yes No
Schematic Reference: Remote Function Schematics 
Connector End View Reference: Remote Function Connector End Views 
1 Did you perform the Diagnostic System Check - Vehicle? Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
IMPORTANT: This condition may be caused by a low vehicle battery voltage. If the battery is not sufficiently charged (above 10 volts), the system will have difficulties detecting the fob and the NO FOBS DETECTED message will be displayed. Correct the low battery voltage condition to eliminate this condition.
With a valid key fob, attempt to start the vehicle.Is the NO FOB DETECTED message displayed on the driver information center (DIC)?		 Go to Step 3  Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3
  1. Exit the vehicle with the key fob.
  2. Lock the vehicle.
  3. Attempt to enter both the driver and passenger doors passively with the key fob.
Are you able to enter the vehicle from both doors?		 Go to Step 4  Go to Keyless Entry System Inoperative (Active)  or Keyless Entry System Inoperative (Passive) 
4
IMPORTANT: Areas of high radio frequency (RF) traffic may cause an intermittent NO FOB DETECTED message. This is a normal condition. If the vehicle is parked in an area of high RF traffic, move vehicle before continuing with diagnostics.
Move the key fob to various places within the vehicle and attempt to start.Does the vehicle start?		 System OK Go to Step 5 
5
  1. Place the key fob in the limp home pocket located in the center console.
  2. Turn ON the ignition with the engine OFF by pressing and holding the ACC button for 5 seconds.
  3. Connect a scan tool to the vehicle.
  4. Check vehicle for any DTCs.
Were any DTCs found?		 Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information Go to Step 6 
6
IMPORTANT: The ignition start button must be pressed to produce the voltage pulse to the passive antenna.
  1. Disconnect the console antenna at the center console.
  2. With the keyless entry transmitter held near the headliner antenna, press the ignition start button.
Does the vehicle start?		 Go to Step 8  Go to Step 7 
7
IMPORTANT:
  • The voltage signal sent by the remote control door lock receiver (RCDLR) to the passive antenna is an AC voltage signal. The DMM must be set on AC voltage setting to record the voltage pulse to the passive antenna.
  • Use a DMM to record the voltage pulse using the MIN MAX setting to capture the AC voltage pulse to the passive antenna.
  • The ignition start button must be pressed to produce the voltage pulse to the passive antenna.
  1. Disconnect the headliner antenna.
  2. With the DMM measure/capture for an AC voltage signal between the keyless entry signal circuit and the low reference circuit.
Was an AC voltage signal captured on the DMM?		 Go to Step 12  Go to Step 9 
8
IMPORTANT:
  • The voltage signal sent by the RCDLR to the passive antenna is an AC voltage signal. The DMM must be set on AC voltage setting to record the voltage pulse to the passive antenna.
  • Use a DMM to record the voltage pulse using the MIN MAX setting to capture the AC voltage pulse to the passive antenna.
  • The ignition start button must be pressed to produce the voltage pulse to the passive antenna.
With the DMM, measure/capture for an AC voltage signal between the console keyless entry antenna signal circuit and the low reference circuit.Was an AC voltage signal captured on the DMM?		 Go to Step 13  Go to Step 10 
9 Test the headliner keyless entry antenna signal circuit and low reference circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 17  Go to Step 11 
10 Test the console keyless entry antenna signal circuit and low reference circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 17  Go to Step 11 
11 Inspect for poor connections at the RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 17  Go to Step 14 
12 Inspect for poor connections at the headliner antenna. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 17  Go to Step 15 
13 Inspect for poor connections at the console antenna. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 17  Go to Step 16 
14 Replace the RCDLR. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 Go to Step 17  -
15 Replace the headliner antenna. Refer to Ignition Lock Key Transmitter Antenna Replacement - Headliner .
Did you complete the replacement?		 Go to Step 17  -
16 Replace the console antenna. Refer to Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Cup Holder)  or Ignition Lock Key Transmitter Antenna Replacement - Floor Console (Rear) .
Did you complete the replacement?		 Go to Step 17  -
17 With a valid key fob, attempt to start the vehicle.
Is the NO FOB DETECTED message displayed on the DIC?		 Go to Step 2  System OK
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