Contents Wiring diagrams Section: Door Locks & Anti-Theft Systems All sections

Keyless Entry System: Overview Chevrolet Tahoe II

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: Lack of communication may be due to a partial malfunction of the class 2 serial data circuit or due to a total malfunction of the class 2 serial data circuit. The specified procedure will determine the particular condition.
  2. 5: The presence of DTCs which begin with "U" indicate some other module is not communicating. The specified procedure will compile all the available information before tests are performed. Any other body control module DTCs displayed by the scan tool do not apply to Remote Keyless Entry and should be diagnosed in the applicable section.
StepActionYesNo
1Install a scan tool. Does the scan tool power up?Go to Step 2Go to SCAN TOOL DOES NOT POWER UP
2Turn ON the ignition, with the engine OFF. Attempt to establish communication with the following control modules. body control module passenger door module Does the scan tool communicate with all of the listed control modules?Go to Step 3Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE
3IMPORTANT: The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode. Access the Class 2 Power Mode in the Diagnostic Circuit Check on the scan tool. Rotate the ignition switch through all positions while observing the ignition switch power mode parameter. Does the ignition switch parameter reading match the ignition switch position for all switch positions?Go to Step 4Go to POWER MODE MISMATCH
4Select the display DTCs function on the scan tool. body control module passenger door module Does the scan tool display any DTCs?Go to Step 5Go to Symptoms - Keyless Entry
5Does the scan tool display any DTCs which begin with a "U"?Go to SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICEGo to DIAGNOSTIC TROUBLE CODE (DTC) LIST
IMPORTANT
The engine may start during the following step. Turn OFF the engine as soon as you have observed the Crank power mode.

Diagnostic System Check - Remote Keyless Entry

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: The normal state of the input displayed on the scan tool before pressing a transmitter button is NONE.
  2. 3: When the UNLOCK button is pressed on the transmitter, Actv Unlock Fob# will be displayed on the scan tool.
  3. 4: The normal state of the input displayed on the scan tool before pressing a transmitter button is NONE.
  4. 5: Tests the signal circuit for a short to ground.
StepActionYesNo
Schematic Reference: Keyless Entry Schematics
1Did you perform the Remote Keyless Entry Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Remote Keyless Entry
2Install a scan tool. Turn ON the ignition, with the engine OFF. With the scan tool, observe the RFA Message Since Wake-up parameter. Does the scan tool display NONE?Go to Step 3Go to Step 4
3Activate the UNLOCK button on the keyless entry transmitter. With the scan tool, observe the RFA Message Since Wake-up parameter. Does the RFA Message Since Wake-up parameter change state?Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONSGo to Step 4
4Turn OFF the ignition. Disconnect the remote control door lock receiver (RCDLR). Turn ON the ignition, with the engine OFF. With a scan tool, observe the RFA Message Since Wake-up parameter. Does the scan tool display NONE?Go to Step 7Go to Step 5
5Test the keyless entry serial data circuit for a short to ground. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you find and correct the condition?Go to Step 10Go to Step 6
6Inspect for poor connections at the harness connector of the body control module (BCM). Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?Go to Step 10Go to Step 8
7Inspect for poor connections at the harness connector of the RCDLR. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?Go to Step 10Go to Step 9
8IMPORTANT: Perform the BCM programming procedure when replacing the BCM. Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT .Did you complete the replacement?Go to Step 10
9Replace the Remote Control Door Lock Receiver. Refer to Remote Control Door Lock Receiver Replacement . Did you complete the replacement?Go to Step 10
10Use a scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?Go to Step 2System OK
IMPORTANT
Perform the BCM programming procedure when replacing the BCM.

DTC B3102

Symptoms - Keyless Entry

IMPORTANTThe following steps must be completed before using the symptom tables. Perform Diagnostic System Check - Remote Keyless Entry before using the Symptom Tables in order to verify that all of the following are true. There are no DTCs set. The control module(s) can communicate via the serial data link. Review the system operation in order to familiarize yourself with the system functions. Refer to Keyless Entry System Description and Operation .

The numbers below refer to the step numbers on the diagnostic table.

  1. 15: This step verifies that the keyless entry serial data circuit is at B+ supplied by the BCM.
  1. 16: This step tests for a short to voltage in the keyless entry serial data circuit.
StepActionYesNo
1Did you perform the Remote Keyless Entry Diagnostic System Check?Go to Step 2Go to Diagnostic System Check - Remote Keyless Entry
2Press each button of the transmitter one at a time. Does the system operate normally?Go to TESTING FOR INTERMITTENT AND POOR CONNECTIONSGo to Step 3
3Lock and unlock the door locks using the controls inside the vehicle. Do the locks operate properly?Go to Step 4Go to DIAGNOSTIC SYSTEM CHECK - DOOR SYSTEMS
4IMPORTANT: Inspect that the keyless entry transmitter is the correct model for the vehicle remote system. A wrong model transmitter may pass this test, but will not activate the vehicle remote system. Turn on the J 43241 Keyless Entry Tester. Place the transmitter on the J 43241 test pad. Press each button of the transmitter one at a time. Does a tone sound and the green light illuminate on the J 43241 after each button is pressed?Go to Step 9Go to Step 5
5Do any of the buttons on the transmitter sound the tone and illuminate the green light when pressed?Go to Step 8Go to Step 6
6Replace the transmitter battery. Refer to Transmitter Battery Replacement . Did you complete the replacement?Go to Step 7
7Turn on the J 43241 Keyless Entry Tester. Place the transmitter on the J 43241 test pad. Press each button of the transmitter one at a time. Does a tone sound and the green light illuminate on the J 43241 after each button is pressed?Go to Step 9Go to Step 8
8Replace the transmitter. Did you complete the replacement?Go to Step 12
9Press the PANIC button on the transmitter. Does the PANIC function operate normally?Go to Step 10Go to Step 12
10Perform the synchronization procedure. Refer to Transmitter Synchronization . Do the locks cycle to lock then unlock?Go to Step 11Go to Step 12
11Operate the transmitter within range of the vehicle. Do all of the Remote Keyless Entry functions operate normally?Go to Step 25Go to Step 12
12IMPORTANT: All transmitters which are to be recognized by the remote control door lock receiver (RCDLR) must be programmed in a single programming sequence. If the system is placed in program mode it will erase all previously programmed transmitters upon the receipt of the programming signal from the first transmitter. Perform the programming procedure. Refer to Transmitter Programming . Do the locks cycle to lock the unlock?Go to Step 25Go to Step 13
13Turn OFF the ignition. Disconnect the RCDLR. Connect a test lamp between the battery positive voltage circuit of the RCDLR and a good ground. Does the test lamp illuminate?Go to Step 14Go to Step 21
14Connect a test lamp between the battery positive voltage circuit and the ground circuit of the RCDLR. Does the test lamp illuminate?Go to Step 15Go to Step 22
15Disconnect the test lamp. Turn ON the ignition, with the engine OFF. Measure the voltage between the keyless entry serial data circuit of the RCDLR and a good ground. Does the voltage measure within the specified range?Go to Step 16Go to Step 18
16Turn ON the ignition, with the engine OFF. Connect a test lamp between the keyless entry serial data circuit of the RCDLR and a good ground. Does the test lamp illuminate?Go to Step 17Go to Step 19
17Test the keyless entry serial data circuit for a short to voltage. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you find and correct the condition?Go to Step 25Go to Step 20
18Test the keyless entry serial data circuit for an open, high resistance, or short to ground. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you find and correct the condition?Go to Step 25Go to Step 20
19Inspect for poor connections at the harness connector of the RCDLR. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?Go to Step 25Go to Step 23
20Inspect for poor connections at the harness connector of the body control module (BCM). Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS . Did you find and correct the condition?Go to Step 25Go to Step 24
21Repair the open, high resistance, or short to ground in the battery positive voltage circuit of the RCDLR. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you complete the repair?Go to Step 25
22Repair the open or high resistance in the RCDLR ground circuit. Refer to CIRCUIT TESTING and WIRING REPAIRS . Did you complete the repair?Go to Step 25
23IMPORTANT: Perform the remote control door lock transmitter programming procedure when replacing the RCDLR. Replace the RCDLR. Refer to Remote Control Door Lock Receiver Replacement . Did you complete the repair?Go to Step 25
24IMPORTANT: Perform the BCM programming procedure when replacing the BCM. Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT . Did you complete the repair?Go to Step 25
25Operate the system in order to verify the repair. Did you correct the condition?System OKGo to Step 3
IMPORTANT
Inspect that the keyless entry transmitter is the correct model for the vehicle remote system. A wrong model transmitter may pass this test, but will not activate the vehicle remote system.
IMPORTANT
All transmitters which are to be recognized by the remote control door lock receiver (RCDLR) must be programmed in a single programming sequence. If the system is placed in program mode it will erase all previously programmed transmitters upon the receipt of the programming signal from the first transmitter. Perform the programming procedure. Refer to Transmitter Programming .
IMPORTANT
Perform the remote control door lock transmitter programming procedure when replacing the RCDLR. Replace the RCDLR. Refer to Remote Control Door Lock Receiver Replacement .
IMPORTANT
Perform the BCM programming procedure when replacing the BCM. Replace the BCM. Refer to BODY CONTROL MODULE REPLACEMENT .

Keyless Entry System Inoperative

Unlock All Doors-Second Operation

Momentarily press the UNLOCK button a second time within 2 seconds of the first press in order to perform the following functions

  1. Unlock the remaining doors.
  2. Illuminate the interior lamps for a predetermined amount of time or until the ignition is turned ON.
  3. Flash the park lamps.