Mitsubishi Sigma P1629 Engine Trouble Code
What is Mitsubishi Sigma P1629?
The Mitsubishi Sigma 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 Sigma
Independent workshop data shows that Mitsubishi Sigma vehicles with P1629 resolve approximately 40% of cases after a throttle body cleaning and idle relearn procedure. This is always the recommended first step before investing in new sensors.
Code Information
| Code Type: | OBD-II Powertrain (P) Trouble Code |
| System: | Powertrain |
| Vehicle: | Mitsubishi Sigma |
| Brand: | Mitsubishi |
| Model: | Sigma |
| Code: | P1629 |
P1629 Mitsubishi Sigma Symptoms
Check Engine Light
Illuminated Mitsubishi Sigma dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Sigma
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Sigma
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 Sigma 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:
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:
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 Sigma P1629 Repair Cost
On the Mitsubishi Sigma, secondary air injection pump replacement for a P1629 code runs $350–$600. Because the pump is only active during cold starts, symptoms are easily missed. Requesting a cold-start emissions test at the workshop will confirm whether the pump is operating.
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 Sigma
When P1629 triggers on the Mitsubishi Sigma, a flashing check-engine light (as opposed to a steady one) indicates an active misfire. Misfire codes are commonly misdiagnosed as sensor faults; always rule out ignition and fuel delivery issues before testing sensors.
DIY Repair Guide: P1629 on Mitsubishi Sigma
Battery terminal cleaning on the Mitsubishi Sigma is a 5-minute job that resolves a surprising number of P1629 intermittents. Use a wire brush and a bicarbonate of soda solution to clean corrosion, then apply a thin coat of petroleum jelly to the terminals after refitting.
Preventing P1629 on the Mitsubishi Sigma
On the Mitsubishi Sigma, using a quality fuel system cleaner (added to the fuel tank every 10,000 miles) helps prevent injector deposit build-up that indirectly triggers P1629 through fuel-trim imbalances.
Frequently Asked Questions — Mitsubishi Sigma P1629
A: It depends on the severity. If the check-engine light is steady, it is generally safe to drive to a workshop within the next few days. If the light is flashing, pull over safely as soon as possible — a flashing light indicates an active misfire that can cause expensive catalytic converter damage within minutes.