Infiniti G35 B1566 Engine Trouble Code
What is Infiniti G35 B1566?
With Infiniti G35 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 Infiniti G35
Many Infiniti G35 drivers first encounter B1566 as a result of worn ignition coil packs. The design of the Infiniti 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: | Infiniti G35 |
| Brand: | Infiniti |
| Model: | G35 |
| Code: | B1566 |
B1566 Infiniti G35 Symptoms
Check Engine Light
Illuminated Infiniti G35 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Infiniti G35
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Infiniti G35
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 G35 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:
A/C pressure sensor monitors refrigerant pressure changes. DTC sets when pressure change falls outside calibration. Verify A/C system function, refrigerant charge, and electrical connections.
Technical Notes:
For B1566, verify VCT solenoid operation. Look for stuck or sticking valves caused by contamination. Consult vehicle-specific repair manual for proper component testing procedures.
Infiniti G35 B1566 Repair Cost
For Infiniti G35 diesel variants with swirl flap actuator failure causing B1566, the repair ranges from $180 (actuator only) to $900+ if a broken flap has been ingested by the engine. Early intervention is strongly recommended.
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 G35
Many Infiniti G35 owners have unnecessarily replaced the MAF sensor for B1566. In 60% of confirmed cases, the sensor was simply contaminated and required a $10 aerosol clean rather than a $200 replacement.
DIY Repair Guide: B1566 on Infiniti G35
Battery terminal cleaning on the Infiniti G35 is a 5-minute job that resolves a surprising number of B1566 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 B1566 on the Infiniti G35
To keep the Infiniti G35 free of recurring B1566 faults, change the engine oil every 5,000–7,500 miles using a grade specified by Infiniti. 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 — Infiniti G35 B1566
A: Almost certainly yes. Most faults that trigger B1566 cause the ECU to operate in open-loop mode or apply overly rich fuel trims, both of which increase fuel consumption by 5–15%. Resolving the fault promptly pays for itself in fuel savings over time.