Citroen 2cv P1629 Engine Trouble Code
What is Citroen 2cv P1629?
The Citroen 2cv P1629 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.
P1629 on the Citroen 2cv
Owners of the Citroen 2cv should be aware that P1629 can appear alongside oil consumption warnings. Low oil pressure caused by a worn PCV system lets crankcase vapour contaminate the mass air flow sensor, sending erroneous readings to the ECU.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Citroen 2cv |
| Brand: | Citroen |
| Model: | 2cv |
| Code: | P1629 |
P1629 Citroen 2cv Symptoms
Check Engine Light
Illuminated Citroen 2cv dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Citroen 2cv
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Citroen 2cv
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 2cv P1629
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:
P1629 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.
Citroen 2cv P1629 Repair Cost
When P1629 appears on a Citroen 2cv, a camshaft position sensor swap costs $140–$260 all-in. This is one of the more affordable sensors on this platform. If the wiring harness is also damaged, add $60–$90 for harness repair or section replacement.
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 2cv
A common error on the Citroen 2cv is attributing P1629 to the crankshaft position sensor when the real fault is a damaged flywheel ring gear. The missing tooth pattern created by ring gear damage is intermittent and generates the same signal anomaly.
DIY Repair Guide: P1629 on Citroen 2cv
The throttle body on the Citroen 2cv can be cleaned without full removal. Use a clean rag and throttle body cleaner spray with the engine off and cool. After cleaning, an idle relearn is mandatory: disconnect the battery for 10 minutes, reconnect, and allow the engine to idle for 10 minutes undisturbed.
Preventing P1629 on the Citroen 2cv
Transmission fluid degradation on the Citroen 2cv directly affects solenoid operation. Replacing ATF at 40,000-mile intervals (rather than the often-quoted 'lifetime fill' recommendation) is the best insurance against shift-solenoid codes including P1629.
Frequently Asked Questions — Citroen 2cv P1629
A: Temporarily clearing P1629 can help determine whether it is intermittent or persistent, but it does not fix the underlying fault. The code will return if the problem is still present. Do not clear codes just before an emissions test without a proper drive cycle.