C0139 Engine Trouble Code
What is C0139?
C0139 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: | C0139 |
C0139 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
C0139 Code Structure
Understanding what each digit means in the C0139 chassis trouble code:
| C | 0 | 1 | 3 | 9 |
|---|---|---|---|---|
| Chassis Code | Intake Valve Control Solenoid Circuit Low | Fuel Rail/System Pressure — Too High | Injection Pump Fuel Metering Control 'A' High | Reverse Input Circuit |
How to Fix C0139
Diagnostic Steps:
Regarding C0139, 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:
Most manufacturers number cylinders sequentially from front to back. Ford V-engines start with cylinder 1 at front left. In V-6 engines, cylinder 4 is front right; in V-8 engines, cylinder 5 occupies that position.
Technical Notes:
For C0139, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
C0139 Description
C0139 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for C0139 OBD-II Engine Trouble Code is: Fuel Rail/System Pressure — Too High.