P1399 Engine Trouble Code
What is P1399?
The P1399 check-engine light can indicate issues ranging from minor (loose gas cap) to serious (catalytic converter failure). Professional diagnostic scanning at a dealer or shop will identify the exact cause and required repairs.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Code: | P1399 |
P1399 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
P1399 Code Structure
Understanding what each digit means in the P1399 powertrain trouble code:
| P | 1 | 3 | 9 | 9 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Throttle/Pedal Position Sensor/Switch A Circuit Intermittent | Crankshaft Position Sensor A Circuit Malfunction | Reverse Input Circuit |
How to Fix P1399
Diagnostic Steps:
Check if fuel pump primes when key is turned to ON. Measure fuel pressure and verify bright white-blue spark at all plugs. Also verify mechanical timing alignment.
Repair Solution:
Brake switch circuit concerns may involve open or shorted BPP circuits, damaged switches, or misadjustment. Verify stoplight function and follow proper self-test procedures per service manual.
Technical Notes:
P1399 DTC indicating a sensor fault does not always mean the sensor itself is bad. The issue may stem from the systems being monitored or even the sensor wiring. Proper diagnosis is essential.
P1399 Description
P1399 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for P1399 OBD-II Engine Trouble Code is: Throttle/Pedal Position Sensor/Switch A Circuit Intermittent.