Infiniti Fx45 B1566 Engine Trouble Code
What is Infiniti Fx45 B1566?
When Infiniti Fx45 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 Infiniti Fx45
On the Infiniti Fx45, 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: | Infiniti Fx45 |
| Brand: | Infiniti |
| Model: | Fx45 |
| Code: | B1566 |
B1566 Infiniti Fx45 Symptoms
Check Engine Light
Illuminated Infiniti Fx45 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Infiniti Fx45
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Infiniti Fx45
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 Infiniti Fx45 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:
Gasoline engines use spark plugs to ignite fuel-air mixture. Proper timing ensures the explosion occurs when the piston is positioned correctly. Incorrect plug wire sequencing causes mistimed ignition, resulting in poor performance.
Technical Notes:
B1566 DTC specifically relates to camshaft timing. When cam timing is over-retarded, the check-engine light illuminates and this code sets. Verify VCT solenoid operation and check for contamination.
Infiniti Fx45 B1566 Repair Cost
VVT actuator replacement on the Infiniti Fx45 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 Infiniti Fx45
A catalytic converter is often condemned on the Infiniti Fx45 when B1566 appears and an efficiency code is present. Before replacement, verify that the upstream oxygen sensor is not slow-responding — a lazy O2 sensor mimics catalytic inefficiency perfectly.
DIY Repair Guide: B1566 on Infiniti Fx45
The throttle body on the Infiniti Fx45 can be cleaned without full removal. Use a clean rag and throttle body cleaner spray with the engine off and cool. After cleaning, an idle relearn is mandatory: disconnect the battery for 10 minutes, reconnect, and allow the engine to idle for 10 minutes undisturbed.
Preventing B1566 on the Infiniti Fx45
Spark plug replacement at the manufacturer's interval — typically 30,000–60,000 miles depending on plug type — is the single most cost-effective preventive maintenance item for avoiding B1566 on the Infiniti Fx45.
Frequently Asked Questions — Infiniti Fx45 B1566
A: Yes. A weak battery causes voltage drop during cranking that confuses the ECU and can store a range of fault codes. Always rule out battery and charging system health before diagnosing sensor-related codes.