2011 Infiniti FX35 ECM: Decoding Part Numbers and Mandatory Programming

Critical Compatibility Warnings for 2011 FX35 ECMs

Symptoms of a Failing ECM

ECM failure can cause a wide range of confusing symptoms because it controls so many different systems. Often, these symptoms can mimic other problems, so it's important to diagnose the issue carefully.

• Check Engine Light: This is often the first and most obvious sign. The light may be constant or intermittent.
• Engine Performance Issues: You might experience stalling, rough idling, hesitation when accelerating, misfires, or a sudden decrease in fuel economy.
• No-Start Condition: The engine may crank but refuse to start. This happens when the ECM fails to control the fuel or spark systems, or when an unprogrammed replacement ECM triggers the anti-theft system.
• No Communication with Scan Tool: If a professional diagnostic scanner cannot establish a connection with the ECM, it's a strong indicator that the module itself has failed.
• Specific Diagnostic Trouble Codes (DTCs): Codes indicating internal processor failure (like P0605 - ROM Error), memory issues (P0603 - Keep Alive Memory Error), or communication failures (U1000 - CAN Communication Line) point towards the ECM.

Diagnosing an ECM Failure

Because a new ECM is expensive and requires programming, it's critical to confirm the ECM is actually the problem. Mechanics treat ECM replacement as a last resort after ruling everything else out.

1. Check the Basics: Ensure the battery is fully charged and the terminals are clean. Check all fuses in the engine bay and cabin fuse boxes.
2. Verify Power and Ground: A mechanic will use a multimeter to check that the ECM is receiving proper voltage and has a solid ground connection at its wiring harness. A bad ground or faulty power relay can mimic a failed ECM.
3. Inspect Wiring: Thoroughly inspect the wiring harness going to the ECM for any signs of damage, corrosion, or loose pins. Pay special attention to areas where the harness might rub against other components.
4. Rule Out Other Components: Test sensors that could cause similar symptoms. For example, a bad crankshaft position sensor can cause a no-start condition but is much cheaper and easier to replace than an ECM.

Buying a Used 2011 FX35 Engine Control Module

A used OEM module is often a reliable and cost-effective alternative to a new one, but you must be careful to get the right part.

Match Your Part Number Exactly

The most important step is to physically inspect your vehicle's original ECM and match the part number. The primary OEM part number for the early 2011 FX35 is 23710-1WW7C. You may also see the Hitachi manufacturer number, such as MEC104-072. Part number 23710-1WW7E is a later version that supersedes the original. Do not buy a module with a different part number unless you have confirmed it is a direct, compatible replacement.

Physical Inspection of a Used Part

When buying a used ECM, look for:

• No Corrosion: Check the aluminum case and the connector pins for any white or green crust, which indicates water damage.
• Intact Seals: The case should not look like it has been pried open.
• Clean Connectors: The pins should be straight and clean. Bent or corroded pins can cause major problems.

Programming and Installation Requirements

This is the most critical part of the replacement process. The ECM is a key component of the Nissan Anti-Theft System (NATS). If you simply swap the module, the car will not start.

Who Can Program the ECM?

Programming this ECM requires specialized equipment and software. Your options are limited:

• Infiniti/Nissan Dealership: They have the proprietary CONSULT diagnostic tool and are guaranteed to be able to program the module. This is the most reliable, though often most expensive, option.
• Specialized Independent Shop: Some high-end independent shops invest in advanced diagnostic tools (like Autel MaxiSYS with a J2534 interface) and the necessary software subscriptions to perform manufacturer-level programming. You must call ahead and confirm they have the specific capability for a 2011 Infiniti ECM replacement.
• Mail-In Programming Services: Some companies offer to pre-program a used ECM with your car's VIN before shipping it to you. This can sometimes create a 'plug-and-play' solution, but may require you to send in your old module for data cloning.

A typical locksmith or general repair shop will not be able to perform this service.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

• Recall 11V551000: There is one safety recall for the 2011 FX35 related to the engine, but it concerns engine oil cooler bolts that could break and cause an oil leak. It does not involve the ECM.
• TSB ITB12-064: Infiniti released a technical service bulletin for 2009-2011 FX35 models to address customer complaints of harsh downshifts, hesitation, and lag. The fix is to reprogram both the ECM and the Transmission Control Module (TCM) with updated software. This is important because even a perfectly functional used ECM may have outdated software. You may want to have the dealer perform this update after installation for the best performance.

Cost Comparison

Prices can vary significantly based on condition and source.

Frequently Asked Questions (FAQ)