P1790 Engine Trouble Code
What is P1790?
The P1790 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: | P1790 |
P1790 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
P1790 Code Structure
Understanding what each digit means in the P1790 powertrain trouble code:
| P | 1 | 7 | 9 | 0 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Rail Pressure Sensor Circuit Malfunction | Crankshaft Position Sensor A Circuit Malfunction | Shift Solenoid E Performance or Stuck Off |
How to Fix P1790
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:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
P1790 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
P1790 Description
P1790 engine trouble code is related to Shift Solenoid E Performance or Stuck Off.
Main Cause
The primary reason for P1790 OBD-II Engine Trouble Code is: Fuel Rail Pressure Sensor Circuit Malfunction.