Mitsubishi Sst B1566 Engine Trouble Code
What is Mitsubishi Sst B1566?
With Mitsubishi Sst B1566, you may drive for several weeks with a malfunctioning MAF sensor, but expect decreased fuel economy and eventual stalling. Shop replacement costs $240–$400 depending on vehicle. The labour is straightforward, with most cost from the part itself.
B1566 on the Mitsubishi Sst
Many Mitsubishi Sst drivers first encounter B1566 as a result of worn ignition coil packs. The design of the Mitsubishi engine bay can trap heat near these components, accelerating wear beyond the typical service interval.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Mitsubishi Sst |
| Brand: | Mitsubishi |
| Model: | Sst |
| Code: | B1566 |
B1566 Mitsubishi Sst Symptoms
Check Engine Light
Illuminated Mitsubishi Sst dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Sst
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Sst
Increased Emissions
Failed emissions test due to B1566
B1566 Code Structure
Understanding what each digit means in the B1566 body trouble code:
| B | 1 | 5 | 6 | 6 |
|---|---|---|---|---|
| Body Code | Fuel And Air Metering | Fuel Composition Sensor Circuit Malfunction | Cylinder 4 Contribution/Balance Fault | Ignition Coil A Primary/Secondary Circuit Malfunction |
How to Fix Mitsubishi Sst B1566
Diagnostic Steps:
Poor running symptoms align with MAP sensor malfunction. In some cases, a faulty MAP sensor will not trigger a code. The issue may represent separate wiring concerns requiring individual diagnosis.
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:
B1566 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 Sst B1566 Repair Cost
VVT actuator replacement on the Mitsubishi Sst for B1566 is a more significant investment: $400–$700 including the oil flush required before fitting the new actuator. Using the correct low-SAPS engine oil after the repair is critical to prevent premature re-failure.
B1566 Description
B1566 engine trouble code is related to Ignition Coil A Primary/Secondary Circuit Malfunction.
Main Cause
The primary reason for B1566 OBD-II Engine Trouble Code is: Fuel Composition Sensor Circuit Malfunction.
Common B1566 Misdiagnosis on the Mitsubishi Sst
Workshop technicians sometimes replace the entire ignition coil assembly on the Mitsubishi Sst when B1566 accompanies a cylinder-specific misfire. In many cases, only the spark plug in the misfiring cylinder has fouled; a $8 plug replaces a $140 coil pack.
DIY Repair Guide: B1566 on Mitsubishi Sst
Replacing the oxygen sensor on the Mitsubishi Sst requires an O2 sensor socket (22mm or 7/8") and penetrating oil applied 24 hours in advance. On vehicles over five years old, the sensor threads often corrode into the bung; heat from a propane torch (briefly applied) is usually sufficient to free them.
Preventing B1566 on the Mitsubishi Sst
To keep the Mitsubishi Sst free of recurring B1566 faults, change the engine oil every 5,000–7,500 miles using a grade specified by Mitsubishi. Oil viscosity directly affects VVT actuator response, and using the wrong grade is one of the most avoidable causes of this code.
Frequently Asked Questions — Mitsubishi Sst B1566
A: Contaminated or low-octane fuel can temporarily trigger B1566 through knock retard and lean/rich excursion events. If the code appeared shortly after a fill-up at an unfamiliar station, running the tank close to empty and refuelling with premium is a sensible first step.