C121C on 2021-2024 Jeep Grand Wagoneer — Manufacturer-Specific Chassis Control Code
1 vehicles · 1 makes · $650-$2,200 repair
Most Reported On
C121C is an OBD-II diagnostic trouble code meaning “Manufacturer-Specific Chassis Control Code.” C121C is an obscure, manufacturer-specific chassis trouble code without an established generic SAE definition. It generally indicates that a chassis control module (ABS, traction/stability, steering, or suspension) detected a fault in a monitored circuit or component, with the hexadecimal suffix indicating a manufacturer-defined condition. The specific component and severity depend entirely on the vehicle make and model. Confirm the definition with factory service information for your exact vehicle before attempting any diagnosis or repair. This code is most commonly reported on 2021-2024 Jeep Grand Wagoneer, with repair costs ranging from $650 to $2,200.
Common Causes
Typical Repair Cost
Based on 1 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose C121C, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
As an Amazon Associate, we earn from qualifying purchases. Prices are approximate and may vary.
FAQ
What does C121C mean?
C121C stands for "Manufacturer-Specific Chassis Control Code." C121C is an obscure, manufacturer-specific chassis trouble code without an established generic SAE definition. It generally indicates that a chassis control module (ABS, traction/stability, steering, or suspension) detected a fault in a monitored circuit or component, with the hexadecimal suffix indicating a manufacturer-defined condition. The specific component and severity depend entirely on the vehicle make and model. Confirm the definition with factory service information for your exact vehicle before attempting any diagnosis or repair.
What are the most common causes of C121C?
The most common causes of C121C are: Wiring or connector fault in the monitored circuit, Faulty sensor or actuator in the chassis system, Open or short circuit (to ground or power), Low or unstable supply voltage / poor ground, Internal control module fault, Connector corrosion or moisture intrusion. The specific cause varies by vehicle.
How much does it cost to fix C121C?
Repair costs for C121C range from $650 to $2,200, depending on the vehicle and root cause.
Which vehicles are affected by C121C?
Au7o has documented C121C across 1 vehicle models from 1 manufacturers: Jeep.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.