C3791 Engine Trouble Code
What is C3791?
With C3791, you may drive for several weeks with a malfunctioning MAF sensor, but expect decreased fuel economy and eventual stalling. Shop replacement costs $240–$400 depending on vehicle. The labour is straightforward, with most cost from the part itself.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C3791 |
C3791 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
C3791 Code Structure
Understanding what each digit means in the C3791 chassis trouble code:
| C | 3 | 7 | 9 | 1 |
|---|---|---|---|---|
| Chassis Code | Ignition System Or Misfire | Fuel Rail Pressure Sensor Circuit Malfunction | Crankshaft Position Sensor A Circuit Malfunction | Crankshaft Position Sensor A Circuit Low Input |
How to Fix C3791
Diagnostic Steps:
Poor running symptoms align with MAP sensor malfunction. In some cases, a faulty MAP sensor will not trigger a code. The issue may represent separate wiring concerns requiring individual diagnosis.
Repair Solution:
Firing order is engineered to minimise vibration. Altering firing order results in mistimed ignition and poor engine operation. Consult vehicle-specific repair manual for correct firing order.
Technical Notes:
C3791 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
C3791 Description
C3791 engine trouble code is related to Crankshaft Position Sensor A Circuit Low Input.
Main Cause
The primary reason for C3791 OBD-II Engine Trouble Code is: Fuel Rail Pressure Sensor Circuit Malfunction.