What Does C1949 Mean?
The stability control module has detected an open circuit in the longitudinal (front-to-back) accelerometer sensor, which measures vehicle acceleration and deceleration forces. This sensor is critical for electronic stability control, traction control, and rollover prevention calculations. Without this input, the ESC system will be disabled. The driver will see the ESC/traction control warning light and may notice these systems do not engage when expected.
Common Causes
35%
Disconnected or damaged connector at the accelerometer sensor
25%
Broken wire in the harness between the accelerometer and the ESC module
20%
Faulty accelerometer sensor with internal open circuit
15%
Corrosion at the sensor connector due to water intrusion (sensor often mounted low on the vehicle)
5%
ESC module connector pin backed out or damaged on the accelerometer circuit
Diagnostic Steps
1
Locate the accelerometer sensor — it is typically mounted on the center tunnel or under the center console, near the vehicle's center of gravity. Some vehicles integrate it into a combined yaw rate/accelerometer sensor cluster. Verify the connector is fully seated.
2
Check for 5V reference voltage and ground at the sensor connector with the sensor disconnected. If 5V reference is missing, trace the wire back to the ESC module.
3
Measure the signal wire(s) for continuity from the sensor connector to the ESC module connector. An open circuit confirms a wiring fault — inspect the harness along its routing path for damage.
4
If wiring checks pass, reconnect the sensor and measure the output voltage with the vehicle on a level surface. A functional longitudinal accelerometer should output approximately 2.5V (mid-scale) at rest. No output or 0V confirms a failed sensor.
5
Check the sensor mounting — it must be securely bolted and properly oriented. A loose mounting can cause sensor readings to be unreliable even if the circuit is electrically intact.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
The stability control module has detected an open circuit in the longitudinal (front-to-back) accelerometer sensor, which measures vehicle acceleration and deceleration forces. This sensor is critical for electronic stability control, traction control, and rollover prevention calculations. Without t...
The most common cause of C1949 (Accelerometer Sensor Circuit Open) is: Disconnected or damaged connector at the accelerometer sensor
Typical repair costs for C1949 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Electronic stability control and traction control are disabled. The vehicle's ability to automatically correct oversteer, understeer, and wheel spin is lost. ABS should still function normally. Drive carefully and avoid aggressive maneuvers, high-speed cornering, and slippery conditions. Repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1949 to identify the root cause.
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Quick Info
Category
Chassis
System
Stability Control / Traction Control
Difficulty
Type
Manufacturer
Recommended Tools
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