P1143 Engine Trouble Code
What is P1143?
P1143 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 Powertrain (P) Trouble Code |
| System: | Powertrain |
| Code: | P1143 |
P1143 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
P1143 Code Structure
Understanding what each digit means in the P1143 powertrain trouble code:
| P | 1 | 1 | 4 | 3 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Rail/System Pressure — Too High | Injection Pump Fuel Metering Control 'B' High | Exhaust Gas Recirculation Sensor B Circuit High |
How to Fix P1143
Diagnostic Steps:
Regarding P1143, 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:
VSS concerns may stem from noisy input signals caused by RFI/EMI from ignition wires, charging circuits, or aftermarket equipment. Verify VSS reads 0 mph when transmission is in Park.
Technical Notes:
P1143 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.
P1143 Description
P1143 OBD-II Trouble Code: Heated Oxygen Sensor 1 Lean Shift Monitoring Bank 1 is one of the definitions for the P1143; however your vehicles manufacturer may have a different definition for the P1143 code. Please check below f
Main Cause
The primary reason for P1143 OBD-II Engine Trouble Code is: Fuel Rail/System Pressure — Too High.