B1990 Engine Trouble Code
What is B1990?
B1990 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 Body (B) Trouble Code |
| System: | Body |
| Code: | B1990 |
B1990 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
B1990 Code Structure
Understanding what each digit means in the B1990 body trouble code:
| B | 1 | 9 | 9 | 0 |
|---|---|---|---|---|
| Body Code | Fuel And Air Metering | Injector Circuit Malfunction - Cylinders | Crankshaft Position Sensor A Circuit Malfunction | Shift Solenoid E Performance or Stuck Off |
How to Fix B1990
Diagnostic Steps:
Regarding B1990, 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 B1990, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
B1990 Description
B1990 engine trouble code is related to Shift Solenoid E Performance or Stuck Off.
Main Cause
The primary reason for B1990 OBD-II Engine Trouble Code is: Injector Circuit Malfunction - Cylinders.