Pinpoint Test G: The Keyless Entry Keypad Illumination Is Inoperative/Does Not Operate Correctly
Handles, Locks, Latches and Entry Systems
Pinpoint Tests
Pinpoint Test G: The Keyless Entry Keypad Illumination Is Inoperative/Does Not Operate Correctly
Refer to Wiring Diagram Set 117, Remote Keyless Entry and Alarm for schematic and connector information. Diagrams By Number
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 help 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 the doors.
- DTC B121A:11 (Keypad Illumination Output: Circuit Short to Ground) - sets when the BCM 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
PINPOINT TEST G: 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.
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G1 CHECK THE KEYLESS ENTRY KEYPAD OPERATION
- Press the 7/8 and 9/0 buttons simultaneously on the keyless entry keypad.
- Do all of the doors lock?
Yes
GO to G2.
No
GO to Pinpoint Test F. Pinpoint Test F: The Doors Do Not Lock/Unlock Using The Keyless Entry Keypad
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G2 CHECK THE RECORDED BCM DTCs FROM THE SELF-TEST
- Check the recorded results from the BCM self-test.
- Is DTC B121A:11 present?
Yes
GO to G9.
No
GO to G3.
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G3 CHECK THE KEYLESS ENTRY KEYPAD ILLUMINATION
- Check the keyless entry keypad illumination.
- Is the keyless entry keypad illumination always on?
Yes
GO to G8.
No
GO to G4.
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G4 CHECK THE KEYPAD ILLUMINATION GROUND CIRCUIT FOR AN OPEN
- Disconnect: Keyless Entry Keypad C500.
- Measure the resistance between the keyless entry keypad C500-4, circuit GD134 (BK/VT), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to G5.
No
REPAIR circuit GD134 (BK/VT) for an open. CLEAR the DTCs. REPEAT the self-test.
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G5 CHECK THE KEYPAD ILLUMINATION CIRCUIT FOR REFERENCE VOLTAGE
NOTE: The BCM sends out a constant reference voltage on circuit CPK28 (WH/GN) for its own circuit diagnostics. This voltage is 10 volts (+/- 1 volt).
- Ignition ON.
- Measure the voltage between the keyless entry keypad C500-7, circuit CPK28 (WH/GN), harness side and ground.
- Is 10 volts (+/- 1 volt) present?
Yes
GO to G6.
No
GO to G7.
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G6 CHECK FOR BCM 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 DataLogger.
- Measure the voltage between the keyless entry keypad C500-7, circuit CPK28 (WH/GN), harness side and ground while active commanding the BCM PID (KEY_PAD_LMP) on.
- Is the voltage greater than 11 volts?
Yes
INSTALL a new keyless entry keypad. REFER to Keyless Entry Keypad Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
GO to G11.
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G7 CHECK THE KEYPAD ILLUMINATION CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect: BCM C2280C.
- Measure the resistance between the keyless entry keypad C500-7, circuit CPK28 (WH/GN), harness side and the BCM C2280C-26, circuit CPK28 (WH/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to G11.
No
REPAIR circuit CPK28 (WH/GN) for an open. CLEAR the DTCs. REPEAT the self-test.
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G8 CHECK THE KEYPAD ILLUMINATION CIRCUIT FOR A SHORT TO VOLTAGE
- Disconnect: BCM 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 G11.
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G9 CHECK THE KEYLESS ENTRY KEYPAD FOR A SHORT TO GROUND
- Disconnect: Keyless Entry Keypad C500.
- Clear the DTCs, then repeat the BCM self-test.
- Is DTC B121A:11 recorded?
Yes
GO to G10.
No
INSTALL a new keyless entry keypad. REFER to Keyless Entry Keypad Service and Repair. TEST the system for normal operation.
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G10 CHECK THE KEYPAD ILLUMINATION CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: BCM C2280C.
- Measure the resistance between the keyless entry keypad C500-7, circuit CPK28 (WH/GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to G11.
No
REPAIR circuit CPK28 (WH/GN) for a short to ground. CLEAR the DTCs. REPEAT the self-test.
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G11 CHECK FOR CORRECT BCM OPERATION
- Disconnect all the BCM connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the BCM 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. REFER to Multifunction Electronic Modules Service and Repair. 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.
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