Mitsubishi Libero P1629 Engine Trouble Code
What is Mitsubishi Libero P1629?
Mitsubishi Libero P1629 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
P1629 on the Mitsubishi Libero
The Mitsubishi Libero features a sequential multi-port fuel injection (SMFI) system where injector timing is tightly synchronised with the crankshaft signal. Wear on the crankshaft reluctor ring teeth produces signal dropout events that accumulate and eventually trigger P1629.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Mitsubishi Libero |
| Brand: | Mitsubishi |
| Model: | Libero |
| Code: | P1629 |
P1629 Mitsubishi Libero Symptoms
Check Engine Light
Illuminated Mitsubishi Libero dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Libero
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Libero
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 Mitsubishi Libero P1629
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
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:
P1629 on electronically controlled automatic transmissions relates to shift solenoid operation. The solenoid actuates hydraulic circuits controlling clutches or bands for gear changes.
Mitsubishi Libero P1629 Repair Cost
For Mitsubishi Libero diesel variants with swirl flap actuator failure causing P1629, the repair ranges from $180 (actuator only) to $900+ if a broken flap has been ingested by the engine. Early intervention is strongly recommended.
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 Mitsubishi Libero
On the Mitsubishi Libero, the VANOS (variable camshaft timing) solenoid is routinely replaced for P1629 when the actual issue is oil pressure insufficiency. No solenoid will operate correctly if the oil pressure required to actuate the VVT phaser is not present.
DIY Repair Guide: P1629 on Mitsubishi Libero
For the Mitsubishi Libero, an EGR valve inspection is a useful DIY step before spending money on diagnosis. Remove the valve (2–4 bolts depending on generation), inspect for carbon build-up, and use carburettor cleaner and a soft brass brush to clean the valve face and seat.
Preventing P1629 on the Mitsubishi Libero
Spark plug replacement at the manufacturer's interval — typically 30,000–60,000 miles depending on plug type — is the single most cost-effective preventive maintenance item for avoiding P1629 on the Mitsubishi Libero.
Frequently Asked Questions — Mitsubishi Libero P1629
A: P1629 is a standardised OBD-II code that can appear on any make and model. However, the specific components and circuits that trigger this code, and the repair procedures involved, vary significantly between vehicles. The information on this page is focused on the Mitsubishi Libero.