Keyless Entry System Malfunction

Circuit/System Description This procedure should be followed for any system malfunction, Service Keyless Start System message, No Remote Detected message, or Key Missing Look For Key message that does not have a DTC present. All of the functions and features of the active and passive keyless entry system, along with the tire pressure monitoring system are tied together through the use of radio frequency to communicate. Determining which features and functions of the systems have failed will suggest what the fault could be and therefore the best diagnostic procedure to follow. The keyless entry transmitters can only be programmed to one vehicle. They can be programmed more than once but only to the same VIN. Once a keyless entry transmitter is programmed to a vehicle it cannot be programmed to a different vehicle but it can be programmed to the same VIN as much as necessary to complete the diagnostic procedures being followed. The keyless entry antennas are used as short range low frequency (LF) transmitters. The LF signal is at 125 kHz. High frequencies are also used by the system and they are 315 MHz except for vehicles built to be certified for use in Japan which are 433 MHz. As a vehicle with locked doors is approached with a keyless entry transmitter (remote key) and the exterior door handle/rear closure touch pad is pressed, the keyless entry antenna broadcasts a challenge to the remote key in an approximate one meter range. If the response from the transmitter via radio frequency (RF) is valid, the locked door will be passively unlocked/unlatched and allow the door to be opened. A low transmitter battery may cause a system malfunction. More often a malfunction is the result of radio frequency (RF) interference from aftermarket devices which could include unexpected items such as nearby flat screen televisions, darkness sensing flood lights, or nearby cell phones. Other more common items that can cause a malfunction are 2-way radios, power inverters, cellular phone chargers, wireless cellular phone chargers, computers, 12 V power outlet USB adapters, etc. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction. Diagnostic Aids The keyless entry antennas must be installed correctly for proper performance. The precise location and orientation are important for the antenna to have the range and shape of range designed for each antenna location. There is a possibility that the passive entry system set a false DTC due to the antenna being incorrectly installed. Unwanted or inadvertent door lock/unlock activation may be requested by the OnStar® Remote Link app. It is possible that a customer may be unaware of account usage, resulting in an unwanted or phantom door lock/unlock. If normal system diagnosis results in an inability to verify the customer’s concern, contact Technical Assistance Center (TAC). Reference Information Schematic Reference Remote Function Schematics Connector End View Reference Master Electrical Component List Description and Operation Keyless Entry System Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Special Tools EL-52545 Tire Pressure Monitor Sensor and RF Diagnostic Tool Circuit/System Verification

Note

The passive entry system unlocking function can be disabled through the transmitter or the center stack. The center stack displays the status of the feature. If the feature is disabled the exterior lights will flash quickly 4 times when the passive entry door button is pressed. Refer to owners manual for more information. In order to determine the best starting point to begin diagnosis first determine which features on the vehicle are functioning correctly or not. By performing a simple and quick check on the vehicle it can be determined if there is or isn’t a fault in each feature. If any one part of the feature is faulty then the feature status is failed. Match the status of all four features and go the suggested link to begin diagnosis. Active Keyless Entry Verification

1. Ignition off, stand approximately 3 meters (15 feet) from the vehicle.
2. Verify the transmitter opens the trunk/rear closure of the vehicle, if equipped.
3. Verify the transmitter locks and unlocks the vehicle.
4. Verify the transmitter other optional functions operate (for example — Panic, Remote Start, Convertible Top). ⇒ If equipped with a trunk/rear closure and not opening or any of the other optional functions Refer to Keyless Entry Transmitter Malfunction in Circuit/System Testing below, ⇓ If the vehicle either does not lock or does not unlock Continue verification of the other functions. This function is Failed. ⇓ If the vehicle locks and unlocks
5. All OK. This function Passed. Passive Starting Function Status

Note

Perform this verification with each of the transmitters separately. If the concern is only present with one transmitter then the fault is likely with the one transmitter.

1. Enter the vehicle, ignition OFF.
2. Repeat this step with each transmitter separately and with the transmitter not being verified located 3 meters (15 feet) from the vehicle. Place the transmitter on the passenger seat and verify the vehicle starts using the start/stop switch then move the transmitter to the rear seat and verify the vehicle starts using the start/stop switch. ⇒ If the vehicle does not start with one transmitter Refer to Keyless Entry Transmitter Malfunction in Circuit/System Testing below. ⇒ If the vehicle does not start with both transmitters  3. Continue verification of the other functions. This function is Failed. ⇓ If the vehicle starts
3. All OK. This function Passed. Passive Entry Function Status, if equipped and if not equipped then ignore the column in the chart

Note

The passive entry system unlocking function can be disabled through the transmitter or the center stack. The center stack displays the status of the feature. If the feature is disabled the exterior lights will flash quickly 4 times when the passive entry door button is pressed. Refer to owners manual for more information.

1. Ignition off, approach the locked vehicle.
2. Verify the trunk/rear closure, if equipped, opens using the passive entry button or touch pad.
3. Verify all the doors unlock and open using the passive entry button or touch pad. ⇒ If one or two doors on the same side do not unlock and open or only the trunk/rear closure does not open Refer to Keyless Entry Antenna Malfunction in Circuit/System Testing below. ⇓ If all the doors do not unlock and open through passive entry Continue verification of the other functions. This function is Failed. ⇓ If all the doors unlock and open through passive entry and the trunk/rear closure opens
4. All OK. This function Passed. Tire Pressure Monitoring System Function Status
5. Ignition on, enter the vehicle.
6. Verify all four tire pressures are displayed. ⇒ If one pressure is not displayed Refer to Symptoms - Tire Pressure Monitoring ⇓ If all of tire pressures do not display This function is Failed. Go to the Circuit/System Testing below as indicated by the Pass/Fail results in the chart. ⇓ If all the tire pressures are displayed
7. All OK. This function Passed. Go to the Circuit/System Testing below as indicated by the Pass/Fail results in the chart.

Active Keyless Entry Function Status	Passive Starting Function Status	Passive Entry Function Status	Tire Pressure Monitoring System Status	Most Probable Diagnostic Starting Point
Passed	Passed	Passed	If one or all four readings are missing	Symptoms - Tire Pressure Monitoring

Active Keyless Entry Function Status	Passive Starting Function Status	Passive Entry Function Status	Tire Pressure Monitoring System Status	Most Probable Diagnostic Starting Point
Failed	Failed	Failed	All four readings are missing	Remote Function Actuator Module Malfunction, below in Circuit/System Testing
Failed	Passed	Passed	All four readings are missing
Passed	Passed	Failed	All four readings are present	Keyless Entry Antenna Malfunction, below in Circuit/System Testing
Passed	Failed	Passed	All four readings are present
Passed	Failed	Failed	Unable to power mode vehicle, readings are unknown
Passed	Failed	Failed	All four readings are present	Keyless Entry Transmitter Malfunction, below in Circuit/System Testing
Failed	Failed	Failed	All four readings are present
Failed	Passed	Passed	All four readings are present
Failed	Passed	Failed	All four readings are present

Circuit/System Testing

Note

The passive entry system unlocking function can be disabled through the transmitter or the center stack. The center stack displays the status of the feature. If the feature is disabled the exterior lights will flash quickly 4 times when the passive entry door button is pressed. Refer to owners manual for more information. Remote Function Actuator Module Malfunction

1. Ignition OFF and all vehicle systems OFF, scan tool disconnected, disconnect the harness connector at the K77 Remote Function Actuator Module. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 30 Ω between the low reference circuit terminal 4 and ground. ⇒ If 30 Ω or greater 2.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 2.2. Test for less than 2 Ω in the low reference circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If less than 30 Ω
3. Ignition ON.
4. Test for greater than 11.5 V between the B+ circuit terminal 1 and ground. ⇒ If 11.5 V or less 4.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 4.2. Test for infinite resistance between the B+ circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If Infinite resistance. 4.3. Test for less than 2 Ω in the B+ circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If greater than 11.5 V
5. Test for 0.001–12 V between the serial data circuit terminal 2 and ground. ⇒ If less than 0.001 V 5.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 5.2. Test for infinite resistance between the serial data circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 5.3. Test for less than 2 Ω in the serial data circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇒ If greater than 12 V 5.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. 5.2. Test for less than 0.001 V between the serial data circuit and ground. ⇒ If 0.001 V or greater, repair the short to voltage on the circuit. ⇒ If less than 0.001 V, replace the K9 Body Control Module. ⇓ If between 0.001–12 V
6. Ignition OFF, disconnect the X8 harness connectors at the K9 Body Control Module, ignition ON.
7. Test for less than 0.001 V between the K9 Body Control Module serial data circuit terminal 17 X8 and ground. ⇒ If 0.001 V or greater Repair the short to voltage on the circuit. ⇓ If less than 0.001 V
8. Ignition OFF.
9. Test for infinite resistance between the K9 Body Control Module serial data circuit terminal 17 X8 and ground. ⇒ If less than infinite resistance Repair the short to ground on the circuit. ⇓ If infinite resistance
10. Test for less than 2 Ω between the K9 Body Control Module serial data circuit terminal 17 X8 and the K77 Remote Function Actuator Module serial data circuit terminal 2. ⇒ If 2 Ω or greater Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
11. Replace the K77 Remote Function Actuator Module.
12. Verify the keyless entry functions operate. ⇒ If the keyless entry functions do not operate Replace the K9 Body Control Module ⇓ If the keyless entry functions operate
13. All OK.

Note

The passive entry system unlocking function can be disabled through the transmitter or the center stack. The center stack displays the status of the feature. If the feature is disabled the exterior lights will flash quickly 4 times when the passive entry door button is pressed. Refer to owners manual for more information. Keyless Entry Antenna Malfunction

1. Verify the scan tool Exterior Driver Door Handle Switch, Exterior Passenger Door Handle Switch, and Trunk Lid Exterior Unlatch Switch parameters change between Active and Inactive while operating their respective exterior door handle/rear closure touch pad. ⇒ If any of the parameters does not change Refer to Exterior Door Handle Switch Malfunction. ⇓ If all of the parameters change
2. All OK.
3. Remove and reinstall the transmitter battery, do not replace the battery. Verify the function .

Note

Verify the antenna is installed correctly and not damaged.

4. Ignition OFF, disconnect the harness connector at the appropriate T10 Keyless Entry Antenna that is related to the fault condition, ignition ON.
5. Test for less than 1 V between the signal circuit terminal 1 and ground. ⇒ If 1 V or greater 5.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. 5.2. Test for less than 1 V between the signal circuit and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module. ⇓ If less than 1 V

Note

When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 000.0 V.

6. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
7. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate exterior door handle/rear closure touch pad.
8. Verify the MAX voltage captured by the DMM is greater than 1 V. ⇒ If 1 V or less 8.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 8.2. Test for infinite resistance between the signal circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 8.3. Test for less than 2 Ω in the signal circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If greater than 1 V
9. Test for less than 1 V between the low reference circuit terminal 2 and ground. ⇒ If 1 V or greater 9.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. 9.2. Test for less than 1 V between the low reference circuit and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module. ⇓ If less than 1 V

Note

When using the MIN MAX function, autorange on the DMM may not function properly. To ensure accurate test results, turn off autorange and manually set the DMM range to 000.0 V.

10. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function. Turn off autorange and manually set the DMM range to 000.0 V.
11. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate exterior door handle/rear closure touch pad.
12. Verify the MAX voltage captured by the DMM is greater than 1 V. ⇒ If 1 V or less 12.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 12.2. Test for infinite resistance between the low reference circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 12.3. Test for less than 2 Ω in the low reference circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If greater than 1V
13. Replace the appropriate T10 Keyless Entry Antenna.
14. Lock the vehicle doors using the keyless entry transmitter. Activate the antenna by operating the appropriate exterior door handle/rear closure touch pad.
15. Verify that the door/rear compartment unlocks and opens when the exterior door handle/rear closure touch pad is operated. ⇒ If the door/rear compartment does not unlock and open Replace the K9 Body Control Module. ⇓ If the door/rear compartment unlocks and opens
16. All OK.

Note

The passive entry system unlocking function can be disabled through the transmitter or the center stack. The center stack displays the status of the feature. If the feature is disabled the exterior lights will flash quickly 4 times when the passive entry door button is pressed. Refer to owners manual for more information. Keyless Entry Transmitter Malfunction

1. Ignition ON.
2. Verify that DTC B1442, B1444, B1446, B1451, B1511, B1513, or B15EE is not set. ⇒ If any of the DTCs are set Refer to Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If none of the DTCs are set
3. Verify the Tire Pressure Monitoring System is functioning by adding air to one tire to see the air pressure display increase. ⇒ If the pressure does not increases Refer to Symptoms - Tire Pressure Monitoring ⇓ If the pressure increases
4. Verify the VIN information for the vehicle transmitter is correct using the EL-52545. ⇒ If the VIN is blank Refer to Remote Control Door Lock and Theft Deterrent Transmitter Programming. ⇒ If the VIN is incorrect This transmitter is not for this vehicle, it may already be programmed to work with a different vehicle but cannot be programmed to this vehicle. ⇓ If the VIN is correct
5. Verify the frequency of the transmitter matches the frequency of the tire pressure monitoring system and the remote control door lock receiver using the EL-52545. ⇒ If the transmitter frequency is incorrect Replace the vehicle transmitter. ⇓ If the transmitter frequency is correct
6. Verify the part number information for the vehicle transmitter is correct using the EL-52545 . ⇒ If the vehicle transmitter part number is incorrect Replace the vehicle transmitter. ⇓ If the vehicle transmitter part number is correct
7. Verify the transmitter output is above 20% on the EL-52545 signal strength meter by pressing a button on the transmitter ten times. ⇒ If the transmitter output is lower than 20% Replace the transmitter battery.

Note

Before replacing the transmitter, inspect the transmitter battery contacts for any corrosion or damage. If no corrosion or damage is found, replace the transmitter battery and retest before replacing the transmitter. ⇓ If the transmitter output is higher than 20%

8. Using the scan tool read the number of transmitters learned in the K9 Body Control Module. Using the EL-52545 read the number of transmitters learned in the transmitter. ⇒ If the transmitters learned is less than the number programmed Program the transmitter. Refer to Remote Control Door Lock and Theft Deterrent Transmitter Programming. ⇓ If the transmitters learned is equal to the number programmed
9. Using the EL-52545 verify the transmitter is responding to the antenna by placing the transmitter next to the EL-52545 and pressing the start/stop button. The EL-52545 should display a high frequency (315 MHz or 433 MHz) reading when the start/stop button is pressed. ⇒ If the high frequency (315 MHz or 433 MHz) response does not display Program the transmitter. Refer to Remote Control Door Lock and Theft Deterrent Transmitter Programming. 9.1. Using the EL-52545 verify the transmitter is responding to the antenna by placing the transmitter next to the EL-52545 and pressing the start/stop button. The EL-52545 should display a high frequency (315 MHz or 433 MHz) reading when the start/stop button is pressed. ⇒ If the high frequency (315 MHz or 433 MHz) does not display. Replace the vehicle transmitter ⇓ If the high frequency (315 MHz or 433 MHz) does display
10. Verify the scan tool Exterior Driver Door Handle Switch, Exterior Passenger Door Handle Switch, and Trunk Lid Exterior Unlatch Switch parameters change between Active and Inactive while operating their respective exterior door handle/rear closure touch pad. ⇒ If any of the parameters does not change Refer to Exterior Door Handle Switch Malfunction or Liftgate System Diagnosis ⇓ If all of the parameters change
11. Lock the vehicle using the courtesy switch.
12. Verify that each door and the rear compartment unlocks and opens by approaching the vehicle with a valid transmitter and operating their respective exterior door handle/rear closure touch pad. ⇒ If both doors and the rear compartment do not unlock/unlatch and open Refer to Remote Function Actuator Module Malfunction in Circuit/System Testing above. ⇒ If only one door or the rear compartment does not unlock/unlatch and open Refer to Keyless Entry Antenna Circuit Malfunction in Circuit/System Testing above. ⇓ If both doors and the rear compartment unlocks/unlatches and opens
13. Verify the vehicle locks and unlocks actively with the transmitter. ⇒ If both doors and the rear compartment do not unlock/unlatch and open Remote Control Door Lock and Theft Deterrent Transmitter Programming. ⇓ If the vehicle locks and unlocks
14. All OK.
15. The concern may be caused by temporary RF interference. Discuss the conditions in which the concern occurs with the customer. RF interference from aftermarket devices such as 2-way radios, power inverters, cellular phone chargers, computers, etc. may cause a system malfunction. High RF traffic areas, such as gas stations which use pay-at-the-pump RF transponders, may also cause interference that could lead to a malfunction. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Remote Control Door Lock and Theft Deterrent Transmitter Programming Control Module References for keyless entry control module replacement, programming, and setup