What Does C1778 Mean?
The power steering system has a failure. This typically applies to electric power steering (EPS) systems where the control module detects the steering assist motor, torque sensor, or control electronics are not functioning properly. The driver may experience a sudden loss of power steering assist.
Safety Warning
Loss of power steering assist makes the vehicle very difficult to steer at low speeds. Do not drive — this is a serious safety hazard, especially in emergency maneuvering situations.
Common Causes
30%
Failed EPS motor or motor driver circuit
25%
Faulty steering torque sensor
20%
Wiring fault in the EPS power supply or signal circuit
15%
Low battery voltage causing EPS shutdown
10%
EPS control module internal failure
Diagnostic Steps
1
Step 1: Check battery voltage — EPS systems require at least 11.5V to operate. Low voltage is a common cause of EPS faults.
2
Step 2: Monitor EPS motor current and torque sensor signals via scan tool live data — verify the torque sensor reads near zero with the wheel centered and changes proportionally with steering input.
3
Step 3: Check the EPS fuse (typically 40-80A) for damage.
4
Step 4: Inspect the EPS connector at the steering column or rack for corrosion and secure connection.
5
Step 5: If the torque sensor and power supply are good but the motor does not assist, the EPS motor or module requires replacement.
Estimated Repair Cost
$400 - $2,000
Parts + labor, varies by vehicle and location
The power steering system has a failure. This typically applies to electric power steering (EPS) systems where the control module detects the steering assist motor, torque sensor, or control electronics are not functioning properly. The driver may experience a sudden loss of power steering assist.
The most common cause of C1778 (Power Steering Failure) is: Failed EPS motor or motor driver circuit
Typical repair costs for C1778 range from $400 to $2,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Loss of power steering assist makes the vehicle very difficult to steer at low speeds. Do not drive — this is a serious safety hazard, especially in emergency maneuvering situations.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1778 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Chassis
System
Power Steering System
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
