GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Remote Function Schematics

DEFINITION: Keyless Entry Not Detected

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

With a valid key fob, attempt to start the vehicle.

Does a message display on the driver information center (DIC) stating, NO FOB DETECTED.

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections

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

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.

Was the vehicle activated?

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.

Did you find any DTCs?

Go to Diagnostic Trouble Code (DTC) List - Vehicle

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.

Was the vehicle activated?

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 .

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 .

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 .

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 .

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 .

Did you find and correct the condition?

Go to Step 17

Go to Step 16

14

Replace the RCDLR. Refer to Control Module References for replacement, setup, and programming.

Is the replacement complete?

Go to Step 17

--

15

Replace the headliner antenna. Refer to Ignition Lock Key Transmitter Antenna Replacement - Headliner .

Is the replacement complete?

Go to Step 17

--

16

Replace the console antenna. Refer to Ignition Lock Key Transmitter Antenna Replacement - Floor Console .

Is the replacement complete?

Go to Step 17

--

17

With a valid key fob, attempt to start the vehicle.

Does a message display on the driver information center (DIC) stating, NO FOB DETECTED?

Go to Step 2

System OK