Mitsubishi Colt B1566 Engine Trouble Code
What is Mitsubishi Colt B1566?
When Mitsubishi Colt B1566 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
B1566 on the Mitsubishi Colt
On the Mitsubishi Colt, a triggered B1566 code almost always warrants an immediate inspection of the exhaust gas recirculation (EGR) system. Carbon build-up inside the EGR valve is a well-documented root cause for this platform.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Mitsubishi Colt |
| Brand: | Mitsubishi |
| Model: | Colt |
| Code: | B1566 |
B1566 Mitsubishi Colt Symptoms
Check Engine Light
Illuminated Mitsubishi Colt dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mitsubishi Colt
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mitsubishi Colt
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 Colt B1566
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Brake switch circuit concerns may involve open or shorted BPP circuits, damaged switches, or misadjustment. Verify stoplight function and follow proper self-test procedures per service manual.
Technical Notes:
B1566 DTC indicating a sensor fault does not always mean the sensor itself is bad. The issue may stem from the systems being monitored or even the sensor wiring. Proper diagnosis is essential.
Mitsubishi Colt B1566 Repair Cost
For Mitsubishi Colt owners, budget the following for a B1566 repair: EGR valve cleaning $80–$120 or replacement $250–$450, intake manifold gasket $120–$200, and a post-repair reset and road test. Total: $350–$650 at an independent garage.
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 Colt
The Mitsubishi Colt knock sensor shares its harness with the coolant temperature sensor. A corroded shared ground causes both sensors to report out-of-range values simultaneously, leading to misdiagnosis of B1566 as a knock sensor fault when the root cause is the shared ground splice.
DIY Repair Guide: B1566 on Mitsubishi Colt
For the Mitsubishi Colt, 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 B1566 on the Mitsubishi Colt
The Mitsubishi Colt heat shield over the exhaust manifold protects the nearby sensor wiring from radiant heat damage. Inspect it for cracks or displacement at every brake service. A $15 replacement shield can prevent $300+ wiring loom repairs.
Frequently Asked Questions — Mitsubishi Colt B1566
A: Yes. Some fault conditions, particularly those involving EVAP system leaks or marginal sensor readings, store codes without producing noticeable drivability symptoms. These are called memory faults and still need to be addressed because they will eventually cause performance issues.