BodyB121B
CautionSeverity: Caution - get it checked when you can
IGBT 2 drive function failure
Key terms: Control module: a small computer that runs one part of the car
1What it means in plain English
A body system has a fault. Depending on the make, this range can include airbags and seat belts, windows, locks and climate control, and also charging, brake, oil or coolant sensors.
2Common causes
- Wiring or connector fault
- Faulty sensor or switch
- Water or corrosion in a connector
- Control module fault
- Low battery voltage
3Can I drive?
Do not assume this code is safe to drive. If it concerns the brakes, brake vacuum, charging/alternator, engine oil or coolant, have it diagnosed before driving. Airbags or seat belts may not work in a crash, and a brake or charging fault can leave the car unsafe or stranded. For convenience systems (windows, locks, climate), have it checked when convenient.
This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.
4Brand data 12
| Brand | Code | Description | System |
|---|---|---|---|
| BYD | B121B | IGBT 2 drive function failure Brand | Body |
| Daewoo | B121B | No description available | Body |
| DFFS | B121B | Tire under-inflation detection button failure Brand | Body |
| Geely | B121B | Front Row Right Side Side Airbag Igniter Resistance Low Brand | Body |
| GM | B121B | No description available | Body |
| Holden | B121B | No description available | Body |
| Honda | B121B | No description available | Body |
| Land Rover | B121B | No description available | Body |
| Opel | B121B | No description available | Body |
| Peugeot | B121B | No description available | Body |
| Proton | B121B | No description available | Body |
| Saab | B121B | No description available | Body |
Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.
5Extended variant codes 9
These 7-character codes are manufacturer-specific variants of B121B and may be reported by some scan tools.
| Brand | Code | Description | System |
|---|---|---|---|
| Mahindra | B121B11 | C-Pillar Left SRSU Short To Ground Brand | Body |
| Mahindra | B121B12 | C-Pillar Left SRSU Short To Battery Brand | Body |
| Mahindra | B121B13 | C-Pillar Left SRSU Open Circuit Brand | Body |
| Mercedes-Benz | B121B49 | Electrical expansion valve 'Exterior heat exchanger' has a malfunction. There is an internal electrical fault. Brand | Body |
| Mahindra | B121B64 | C-Pillar Left SRSU Configuration Error Brand | Body |
| Mahindra | B121B81 | C-Pillar Left SRSU Communication Error Brand | Body |
| Mercedes-Benz | B121B87 | Electrical expansion valve 'Exterior heat exchanger' has a malfunction. The message is missing. Brand | Body |
| Mahindra | B121B96 | C-Pillar Left SRSU Internal Error Brand | Body |
| Mercedes-Benz | B121B98 | Electrical expansion valve 'Exterior heat exchanger' has a malfunction. The component or the system has overtemperature. Brand | Body |
6Related codes
Browse Bxxx codes or B121xx codes.