C0401 Engine Trouble Code
What is C0401?
C0401 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C0401 |
C0401 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
C0401 Code Structure
Understanding what each digit means in the C0401 chassis trouble code:
| C | 0 | 4 | 0 | 1 |
|---|---|---|---|---|
| Chassis Code | Intake Valve Control Solenoid Circuit Low | O2 Sensor Heater Circuit Malfunction | Cold Start Injector 1 Malfunction | Crankshaft Position Sensor A Circuit Low Input |
How to Fix C0401
Diagnostic Steps:
Regarding C0401, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
Repair Solution:
Firing order is engineered to minimise vibration. Altering firing order results in mistimed ignition and poor engine operation. Consult vehicle-specific repair manual for correct firing order.
Technical Notes:
C0401 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
C0401 Description
C0401 engine trouble code is related to Crankshaft Position Sensor A Circuit Low Input.
Main Cause
The primary reason for C0401 OBD-II Engine Trouble Code is: O2 Sensor Heater Circuit Malfunction.