Peugeot 5008 P1799 Engine Trouble Code
What is Peugeot 5008 P1799?
With Peugeot 5008 P1799, 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.
P1799 on the Peugeot 5008
The Peugeot 5008 has a known weak point in the lambda sensor wiring loom where it passes through the floor pan grommet. Road salt and vibration cause the insulation to crack at this point, creating an intermittent open circuit that stores P1799 without a consistent symptom.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Peugeot 5008 |
| Brand: | Peugeot |
| Model: | 5008 |
| Code: | P1799 |
P1799 Peugeot 5008 Symptoms
Check Engine Light
Illuminated Peugeot 5008 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Peugeot 5008
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Peugeot 5008
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 5008 P1799
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:
Power steering pressure switch monitors system operation. If pressure changes are not detected after calibrated speed transitions, this DTC sets. Verify PSP switch operation and check for circuit opens or shorts.
Technical Notes:
P1799 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.
Peugeot 5008 P1799 Repair Cost
Throttle body cleaning and idle relearn on the Peugeot 5008 for a P1799 diagnosis costs $60–$100 at an independent shop. If a full throttle body replacement is needed (rare), expect $250–$450 including programming the unit to the ECU.
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 5008
The Peugeot 5008 is frequently taken to workshops for a P1799 fault where the technician replaces the throttle position sensor (TPS). In a significant proportion of cases, the root cause is a loose or cracked vacuum hose downstream of the throttle body that should have been found in a basic visual inspection.
DIY Repair Guide: P1799 on Peugeot 5008
Clearing P1799 on your Peugeot 5008 with a basic OBD-II reader ($20–$40) is straightforward: plug the reader into the diagnostic port under the dashboard, read the stored code, and clear it. If it returns within one drive cycle, the underlying fault is still present and requires attention.
Preventing P1799 on the Peugeot 5008
Ensure the Peugeot 5008 oil cap and dipstick tube seal are airtight. Even a small crank-case vacuum leak can cause the PCM to log P1799 and, over time, allows moisture-laden air to degrade the engine oil faster than the scheduled service interval.
Frequently Asked Questions — Peugeot 5008 P1799
A: Simple fixes like a purge valve or gas cap replacement take under an hour. Sensor replacements typically require 1–2 hours of shop time. More involved repairs like VVT actuators or catalytic converters may require a full day or more.