Citroen C4 Ii P1629 Engine Trouble Code
What is Citroen C4 Ii P1629?
With Citroen C4 Ii P1629, 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.
P1629 on the Citroen C4 Ii
Diesel variants of the Citroen C4 Ii trigger P1629 most often due to swirl flap actuator failure. The plastic actuator arm breaks and the flap defaults to the closed position, causing severe intake restriction and the associated fault flag.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Citroen C4 Ii |
| Brand: | Citroen |
| Model: | C4 Ii |
| Code: | P1629 |
P1629 Citroen C4 Ii Symptoms
Check Engine Light
Illuminated Citroen C4 Ii dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Citroen C4 Ii
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Citroen C4 Ii
Increased Emissions
Failed emissions test due to P1629
P1629 Code Structure
Understanding what each digit means in the P1629 powertrain trouble code:
| P | 1 | 6 | 2 | 9 |
|---|---|---|---|---|
| Powertrain Code | Fuel And Air Metering | Fuel Temperature Sensor B Circuit Range/Performance | Turbocharger Boost Sensor A Circuit Low | Reverse Input Circuit |
How to Fix Citroen C4 Ii P1629
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:
A/C pressure sensor monitors refrigerant pressure changes. DTC sets when pressure change falls outside calibration. Verify A/C system function, refrigerant charge, and electrical connections.
Technical Notes:
For P1629, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
Citroen C4 Ii P1629 Repair Cost
Replacing the lambda (O2) sensor wiring loom section on the Citroen C4 Ii costs $90–$160 at a body shop or auto-electrician. This is far cheaper than replacing the sensor itself when the sensor is otherwise functional — always inspect wiring before condemning sensors.
P1629 Description
P1629 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for P1629 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.
Common P1629 Misdiagnosis on the Citroen C4 Ii
The Citroen C4 Ii purge valve for the EVAP system is located in an area prone to heat damage. It is often overlooked in favour of replacing the carbon canister ($120–$200) when the valve itself ($25–$50) is the failed component for P1629.
DIY Repair Guide: P1629 on Citroen C4 Ii
The Citroen C4 Ii EVAP purge solenoid valve is accessible without lifting the vehicle — it is mounted on the intake manifold and secured by a single bolt and a vacuum hose clip. DIY replacement is rated 1/5 difficulty and takes approximately 20 minutes.
Preventing P1629 on the Citroen C4 Ii
For turbocharged Citroen C4 Ii models, allowing the engine to idle for 60–90 seconds before shutdown after hard driving reduces turbocharger heat soak and prevents the coking of oil that blocks VVT galleries — a known secondary trigger of P1629.
Frequently Asked Questions — Citroen C4 Ii P1629
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.