C1230 C0xxx · Chassis (C) Medium severity
Stability System Longitudinal Acceleration Sensor Fault
The longitudinal acceleration input used by stability and hill-hold functions is missing or implausible.
Severity guidance: Medium — drivability or emissions affected, book it in this week
Symptoms you will notice
- ESP warning lamp
- Hill-start assist unavailable
- Possible false intervention
Common causes
Ordered from most to least likely — start at the top.
- 1 Failed sensor inside the ESP unit or separate module
- 2 Lost calibration
- 3 CAN fault
- 4 Mounting disturbed
How to diagnose it
Cheapest and least invasive first — most of these codes are not a parts problem.
- ✓ Read live longitudinal acceleration with the vehicle level and stationary.
- ✓ Check the sensor mounting orientation.
- ✓ Run the zero-point calibration.
- ✓ Look for CAN faults if the sensor is external.
Repair options
- Replace and calibrate the sensor
- Repair the wiring
- Re-mount and recalibrate
C1230 — frequently asked questions
Why does hill-start assist stop working? +
It needs a trustworthy longitudinal acceleration value to judge the gradient.
Can a level sensor be off but look fine? +
Yes — a slightly tilted module reads a constant false acceleration. Calibration confirms it.
Confirm the diagnosis before you buy parts
Send us the code, freeze-frame data and the vehicle — our engineers will tell you what to test first.