Peugeot Sesame P1799 Engine Trouble Code
What is Peugeot Sesame P1799?
When Peugeot Sesame P1799 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
P1799 on the Peugeot Sesame
Independent workshop data shows that Peugeot Sesame vehicles with P1799 resolve approximately 40% of cases after a throttle body cleaning and idle relearn procedure. This is always the recommended first step before investing in new sensors.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Peugeot Sesame |
| Brand: | Peugeot |
| Model: | Sesame |
| Code: | P1799 |
P1799 Peugeot Sesame Symptoms
Check Engine Light
Illuminated Peugeot Sesame dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Peugeot Sesame
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Peugeot Sesame
Increased Emissions
Failed emissions test due to P1799
P1799 Code Structure
Understanding what each digit means in the P1799 powertrain trouble code:
| P | 1 | 7 | 9 | 9 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Rail Pressure Sensor Circuit Malfunction | Crankshaft Position Sensor A Circuit Malfunction | Reverse Input Circuit |
How to Fix Peugeot Sesame P1799
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
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:
P1799 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
Peugeot Sesame P1799 Repair Cost
On the Peugeot Sesame, secondary air injection pump replacement for a P1799 code runs $350–$600. Because the pump is only active during cold starts, symptoms are easily missed. Requesting a cold-start emissions test at the workshop will confirm whether the pump is operating.
P1799 Description
P1799 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for P1799 OBD-II Engine Trouble Code is: Fuel Rail Pressure Sensor Circuit Malfunction.
Common P1799 Misdiagnosis on the Peugeot Sesame
Some Peugeot Sesame models have a known software bug where the PCM flags P1799 after battery disconnection and reconnect. Always perform an ECU adaptation reset and drive cycle before ordering any parts following battery work.
DIY Repair Guide: P1799 on Peugeot Sesame
The fuel pressure test on the Peugeot Sesame requires a Schrader-valve type fuel pressure gauge ($25–$40) connected to the fuel rail test port. With the ignition ON (engine off), pressure should hold above 30 PSI for two minutes. A rapid drop confirms a leaking injector or failing regulator as the root cause of P1799.
Preventing P1799 on the Peugeot Sesame
The Peugeot Sesame EVAP system requires the fuel tank breather hoses to be flexible and crack-free. A visual inspection at every oil change prevents the slow vacuum leak that triggers P1799 without any drivability symptom.
Frequently Asked Questions — Peugeot Sesame P1799
A: Almost certainly yes. Most faults that trigger P1799 cause the ECU to operate in open-loop mode or apply overly rich fuel trims, both of which increase fuel consumption by 5–15%. Resolving the fault promptly pays for itself in fuel savings over time.