B121B Code: Meaning, Causes, and Symptoms | OBD2 Codes

B121B – Keypad Input Switch


B121B Possible Symptoms


Engine Light ON (or Service Engine Soon Warning Light)


B121B Possible Causes


Faulty Keypad Input Switch,Keypad Input Switch harness is open or shorted,Keypad Input Switch circuit poor electrical connection,Faulty Body Control Module (BCM)


B121B Description


The keypad feature operates independently of key position status, vehicle speed, or transmission position. When a keypad button is touched, the keypad buttons illuminate to provide better visibility. The keypad is also illuminated any time that the courtesy lighting is on. If the lock all doors command is entered or 5 seconds have elapsed since the last button press, the illumination is turned off. Each vehicle equipped with a keypad is programmed with a 5-digit entry code. This code is provided to the customer through a wallet card in the Owner’s Literature. In addition, this code is available through a scan tool and is also printed on the BCM label. When entering codes each digit must be entered within 5 seconds of the previous button press. A DTC that sets when the BCM detects a short to ground on any of the keyless entry keypad input circuits.