Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test N: The Doors Do Not Lock Or Unlock Using The Keyless Entry Keypad
- Refer to REMOTE KEYLESS ENTRY AND ALARM
for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Handles, Locks, Latches and Entry Systems - System Operation and Component Description .
DTC Fault Trigger Conditions
DTC Description Fault Trigger Condition BCM B121B:01 Keypad Input Switch: General Electrical Failure Sets when the BCM detects an internal failure with the driver side keypad. Possible Sources
- Wiring, terminals or connectors
- Keyless entry keypad
- BCM
Visual Inspection and Pre-checks
- Inspect the front door window moulding for damage.
- N1 CHECK POWER LOCK OPERATION FROM THE DOOR LOCK CONTROL SWITCH
- Press the lock and unlock button on the door lock control switch.
Do the doors lock and unlock?
Yes GO to N2 No REFER to the Symptom Chart: Handles, Locks, Latches and Entry Systems - Electrical . - N2 CHECK FOR BCM (BODY CONTROL MODULE) DTC (DIAGNOSTIC TROUBLE CODE) B121B:01
- Ignition ON.
- Using a diagnostic scan tool, carry out the BCM self-test.
Is DTC B121B:01 present?
Yes GO to N3 No GO to N5 - N3 ISOLATE THE KEYLESS ENTRY KEYPAD
- Ignition OFF.
- Disconnect Keyless Entry Keypad C500.
- Ignition ON.
- Using a diagnostic scan tool, clear the Diagnostic Trouble Codes (DTCs) and repeat the BCM self-test.
Is DTC B121B:01 still present?
Yes GO to N4 No INSTALL a new keyless entry keypad. REFER to: Keyless Entry Keypad . - N4 CHECK THE KEYLESS ENTRY KEYPAD INPUT CIRCUITS FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect BCM C2280E.
Are the resistances greater than 10, 000 ohms?
Yes GO to N11 No REPAIR the circuit in question. - N5 CHECK THE BCM (BODY CONTROL MODULE) KEYPAD CODE
- Using a diagnostic scan tool, view the factory keyless entry code.
- Enter the 5-digit factory set entry code on the keyless entry keypad, then touch the 3/4 button.
- Simultaneously touch the 7/8 and 9/0 buttons for 3 seconds.
Do the doors unlock when the factory code is entered and lock when the 7/8 and 9/0 buttons are pressed?
Yes The system is operating as designed. INFORM the customer of the correct system operation. No GO to N6 - N6 CHECK THE BCM (BODY CONTROL MODULE) KEYPAD PARAMETER IDENTIFICATIONS (PIDS)
- Using a diagnostic scan tool, view the BCM Parameter Identifications (PIDs).
- Press each keyless entry keypad button while observing the following BCM Parameter Identifications (PIDs):
- Access the BCM and monitor the KYPD_BTN_1/2PID
- Access the BCM and monitor the KYPD_BTN_3/4PID
- Access the BCM and monitor the KYPD_BTN_5/6PID
- Access the BCM and monitor the KYPD_BTN_7/8PID
- Access the BCM and monitor the KYPD_BTN_9/0PID
Do all of the Parameter Identifications (PIDs) indicate the buttons operate correctly?
Yes GO to N11 No GO to N7 - N7 CHECK THE KEYLESS ENTRY KEYPAD GROUND CIRCUIT FOR AN OPEN
- Ignition OFF.
- Disconnect Keyless Entry Keypad C500.
- Measure:
Positive Lead Measurement / Action Negative Lead C500-6 Ground
Is the resistance less than 3 ohms?
Yes GO to N8 No REPAIR the circuit. - N8 BYPASS THE KEYLESS ENTRY KEYPAD
- Ignition ON.
- Using a diagnostic scan tool, monitor the following BCM Parameter Identifications (PIDs):
- Access the BCM and monitor the KYPD_BTN_1/2PID
- Access the BCM and monitor the KYPD_BTN_7/8PID
- Access the BCM and monitor the KYPD_BTN_9/0PID
- Remove the fused jumper wire.
- Remove the fused jumper wire.
- Remove the fused jumper wire.
Do the Parameter Identifications (PIDs) indicate correctly when the jumper wire is connected?
Yes INSTALL a new keyless entry keypad. REFER to: Keyless Entry Keypad . No GO to N9 - N9 CHECK THE KEYLESS ENTRY KEYPAD INPUT CIRCUITS FOR AN OPEN
- Ignition OFF.
- Disconnect BCM C2280E.
- Measure:
Positive Lead Measurement / Action Negative Lead C500-1 C2280E-28 C500-3 C2280E-2 C500-5 C2280E-15
Are the resistances less than 3 ohms?
Yes GO to N10 No REPAIR the circuit in question. - N10 CHECK THE KEYLESS ENTRY KEYPAD INPUT CIRCUITS FOR A SHORT TO EACH OTHER
Are the resistances greater than 10, 000 ohms?
Yes GO to N11 No REPAIR the circuits in question. - N11 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION
- Disconnect and inspect all the BCM connectors.
- Repair:
- corrosion (install new connectors or terminals - clean module pins)
- damaged or bent pins - install new terminals pins
- pushed-out pins - install new pins as necessary
- Reconnect the BCM connectors and make sure they seat and latch correctly.
- Operate the system and determine if the concern is still present.
Is the concern still present?
Yes CHECK OASIS for any applicable service articles: TSB, GSB, SSM, or FSA. If a service article exists for this concern, DISCONTINUE this test and FOLLOW the service article instructions. If no service articles address this concern, INSTALL a new BCM. REFER to: Body Control Module (BCM) . No The system is operating correctly at this time. The concern may have been caused by module connections. ADDRESS the root cause of any connector or pin issues.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.