Pinpoint Test H: The Keyless Entry Keypad Illumination Is Inoperative/Does Not Operate Correctly
Handles, Locks, Latches and Entry Systems - Without Intelligent Access (IA)
Pinpoint Test H: The Keyless Entry Keypad Illumination Is Inoperative/Does Not Operate Correctly
Normal Operation
When any keypad button is pressed the Body Control Module (BCM) sends voltage to the keyless entry keypad LEDs on the illumination circuit to assist the driver in entering an access code at night. The keyless entry keypad has a separate ground circuit for the LEDs.
The keyless entry keypad has an anti-scan feature to prevent theft. If a valid 5-digit code is not entered within 7 attempts (35 consecutive button presses), the keyless entry keypad goes into anti-scan mode. In anti-scan mode, the keypad illumination flashes and all input is ignored except for pressing the 7/8 and 9/0 buttons, which locks all of the doors.
- DTC B121A:11 (Keypad Illumination Output: Circuit Short to Ground)- sets when the BCM (Body Control Module) detects a short to ground on the keyless entry keypad illumination circuit.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Keyless entry keypad
- BCM (Body Control Module)
PINPOINT TEST H : THE KEYLESS ENTRY KEYPAD ILLUMINATION IS INOPERATIVE/DOES NOT OPERATE CORRECTLY
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
NOTE: Failure to disconnect the battery when instructed results in false resistance readings.
H1 CHECK THE KEYLESS ENTRY KEYPAD OPERATION
- Press the 7/8 and 9/0 buttons simultaneously on the keypad.
Do the doors lock using the keyless entry keypad?
Yes
GO to H2.
No
GO to Pinpoint Test G. Pinpoint Test G: The Doors Do Not Lock/Unlock Using The Keyless Entry Keypad
H2 CHECK THE RECORDED BCM (Body Control Module) DTCs FROM THE SELF-TEST
- Check the recorded results from the BCM (Body Control Module) self-test.
Is DTC B121A:11 present?
Yes
GO to H9.
No
GO to H3.
H3 CHECK THE KEYLESS ENTRY KEYPAD ILLUMINATION
- Ignition OFF.
- Check the keyless entry keypad illumination.
Is the keyless entry keypad illumination always on?
Yes
GO to H8.
No
GO to H4.
H4 CHECK THE KEYPAD ILLUMINATION OUTPUT CIRCUIT FOR REFERENCE VOLTAGE
NOTE: The BCM (Body Control Module) sends out a constant reference voltage on circuit CPK28 (WH/GN) for its own circuit diagnostics. This voltage is 10 volts +/- 1 volt.
- Disconnect: Keyless Entry Keypad C500.
- Measure the voltage between the keyless entry keypad C500-6, circuit CPK28 (WH/GN), harness side and ground.
Is 10 volts (+/- 1 volt) present?
Yes
GO to H5.
No
GO to H7.
H5 CHECK FOR SJB (Smart Junction Box) OUTPUT
NOTE: This pinpoint test checks for a voltage increase above the reference voltage checked in the previous pinpoint test when the keypad lamp is active commanded on.
- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) DataLogger.
- Measure the voltage between the keyless entry keypad C500-6, circuit CPK28 (WH/GN), harness side and ground while active commanding the BCM (Body Control Module) PID (KEY_PAD_LMP) ON.
Is the voltage greater than 11 volts?
Yes
GO to H6.
No
GO to H11.
H6 CHECK THE KEYPAD ILLUMINATION GROUND CIRCUIT FOR AN OPEN
- Disconnect: Negative Battery Cable.
- Measure the resistance between the keyless entry keypad C500-3, circuit GD133 (BK), harness side and ground.
Is the resistance less than 5 ohms?
Yes
INSTALL a new keyless entry keypad. REFER to Keyless Entry Keypad Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR circuit GD133 (BK) for an open. CLEAR the DTCs. REPEAT the self-test.
H7 CHECK THE KEYPAD ILLUMINATION OUTPUT CIRCUIT FOR AN OPEN
- Disconnect: BCM (Body Control Module) C2280C.
- Measure the resistance between the keyless entry keypad C500-6, circuit CPK28 (WH/GN), harness side and the BCM (Body Control Module) C2280C-26, circuit CPK28 (WH/GN), harness side.
Is the resistance less than 5 ohms?
Yes
GO to H11.
No
REPAIR circuit CPK28 (WH/GN) for an open. CLEAR the DTCs. REPEAT the self-test.
H8 CHECK THE KEYPAD ILLUMINATION OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: BCM (Body Control Module) C2280C.
- Ignition ON.
- Observe the keypad illumination.
Is the keypad still illuminated?
Yes
REPAIR circuit CPK28 (WH/GN) for a short to voltage. CLEAR the DTCs. REPEAT the self-test.
No
GO to H11.
H9 CHECK THE KEYLESS ENTRY KEYPAD FOR A SHORT TO GROUND
- Disconnect: Keyless Entry Keypad C500.
- Clear the DTCs, then repeat the BCM (Body Control Module) self-test.
Is DTC B121A:11 recorded?
Yes
GO to H10.
No
INSTALL a new keyless entry keypad. REFER to Keyless Entry Keypad Service and Repair. TEST the system for normal operation.
H10 CHECK THE KEYPAD ILLUMINATION OUTPUT CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM (Body Control Module) C2280C.
- Measure the resistance between the keyless entry keypad C500-6, circuit CPK28 (WH/GN), harness side and ground.
Is the resistance greater than 10,000 ohms?
Yes
GO to H11.
No
REPAIR circuit CPK28 (WH/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
H11 CHECK FOR CORRECT BCM (Body Control Module) OPERATION
- Disconnect all the BCM (Body Control Module) connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM (Body Control Module) connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new BCM (Body Control Module). TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.