C3987 Engine Trouble Code
What is C3987?
C3987 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C3987 |
C3987 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
C3987 Code Structure
Understanding what each digit means in the C3987 chassis trouble code:
| C | 3 | 9 | 8 | 7 |
|---|---|---|---|---|
| Chassis Code | Ignition System Or Misfire | Injector Circuit Malfunction - Cylinders | Ignition/Distributor Engine Speed Input Circuit Malfunction | Shift/Timing Solenoid Malfunction |
How to Fix C3987
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
Repair Solution:
Gasoline engines use spark plugs to ignite fuel-air mixture. Proper timing ensures the explosion occurs when the piston is positioned correctly. Incorrect plug wire sequencing causes mistimed ignition, resulting in poor performance.
Technical Notes:
C3987 DTC specifically relates to camshaft timing. When cam timing is over-retarded, the check-engine light illuminates and this code sets. Verify VCT solenoid operation and check for contamination.
C3987 Description
C3987 engine trouble code is related to Shift/Timing Solenoid Malfunction.
Main Cause
The primary reason for C3987 OBD-II Engine Trouble Code is: Injector Circuit Malfunction - Cylinders.