1990 Mitsubishi Sigma Service and Repair Manual

This factory service and repair manual for the 1990 Mitsubishi Sigma covers a car powered by a 181-cubic-inch engine, a 3.0L V6 with a single overhead camshaft layout, natural aspiration and gasoline fuel. The body is a 4-door sedan, and Base is the trim. For the engine, the manual provides specifications and diagnostics covering fuel, ignition and cooling; for the chassis, procedures and torque values for the transaxle, brakes, suspension and steering; and for the electrical system, wiring diagrams.

Engines covered

• 3.0L V6 (181 cu in) — SOHC, naturally aspirated, gasoline

Body styles covered

• 4-door sedan

Trims covered

• Base

Known issues on the 1990 Sigma. Two owner complaints name the 1990 Sigma, and both involve the seat belts; 1 also cites the engine and engine cooling. Separately, the federal record holds 1 recall, covering certain 1990 Sigma vehicles with front belts supplied by Takata. Their red release buttons could fracture, and loose pieces could jam the buckle mechanism so it no longer worked as intended, reducing crash protection. The remedy had owners check both front buckles and get a dealer to fix or replace a bad one free. Diagnostics and procedures for the body, cooling system and engine support these areas.