Mitsubishi Jeep P1629 Engine Trouble Code
What is Mitsubishi Jeep P1629?
The Mitsubishi Jeep 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 Mitsubishi Jeep
Owners of the Mitsubishi Jeep 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: | Mitsubishi Jeep |
| Brand: | Mitsubishi |
| Model: | Jeep |
| Code: | P1629 |
P1629 Mitsubishi Jeep Symptoms
Check Engine Light
Illuminated Mitsubishi Jeep dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Jeep
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Jeep
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 Jeep 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.
Mitsubishi Jeep P1629 Repair Cost
Replacing the lambda (O2) sensor wiring loom section on the Mitsubishi Jeep 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 Mitsubishi Jeep
Some Mitsubishi Jeep models have a known software bug where the PCM flags P1629 after battery disconnection and reconnect. Always perform an ECU adaptation reset and drive cycle before ordering any parts following battery work.
DIY Repair Guide: P1629 on Mitsubishi Jeep
The Mitsubishi Jeep 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 Mitsubishi Jeep
The Mitsubishi Jeep coolant temperature sensor plays a role in fuel enrichment during warm-up. Replacing it as a precaution at 80,000 miles ($25–$40 DIY) prevents the faulty cold-start enrichment that can lead to P1629.
Frequently Asked Questions — Mitsubishi Jeep 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.