1995-1998 Nissan 240SX Access Control Module: Fixing Door Lock & Alarm Faults
This guide covers the common failures, part numbers, and replacement of the Smart Entrance Control Unit for the S14 Nissan 240SX, including the critical differences between models with and without keyless entry.
- The module is plug-and-play and does NOT require programming, making a used part a great value.
- You MUST match the part number to your car's options: 28595-70F00 for non-keyless entry, and 28595-70F10 for factory keyless entry.
- Failure of a single door lock is almost always the actuator in that door, not this central module.
- The module is located behind the passenger-side kick panel, above the main ECU.
Symptoms of a Failing Access Control Module
When the Smart Entrance Control Unit begins to fail, it can cause a variety of frustrating electrical issues. It's important to distinguish its symptoms from those of a faulty door lock actuator. Typically, if only one door has a problem, the issue is the actuator in that door; if both doors malfunction at the same time, the control unit is a likely suspect.
- Power Locks Don't Work: Neither the driver nor passenger side power lock switch will lock or unlock the doors.
- Intermittent Lock Operation: The door locks may work sometimes but not others, or they may seem to lock or unlock on their own.
- Factory Alarm Issues: The factory security system may not arm or disarm correctly, or the alarm may trigger for no reason.
- No-Crank Condition (with Aftermarket Alarms): In some cases, a failing module can cause a no-start or no-crank condition if a previous owner has installed an aftermarket alarm that interrupts the starter circuit and is wired into the factory unit.
- Dome Light or Chime Problems: The interior dome light may not turn on when the door is opened, or the key-in-ignition warning chime may not function correctly.
Known Issues, Recalls, and TSBs
As of mid-2026, there are no specific Technical Service Bulletins (TSBs) or safety recalls issued by the NHTSA for the Smart Entrance Control Unit on the 1995-1998 Nissan 240SX. Most issues are related to normal age and wear of the electronic components. The most common problem reported by owners is the failure of the power locking system, which can be traced back to this module or the individual door lock actuators.
Pro Tip: Before replacing the module, always check the simple things first. Inspect the "DOOR LOCK" fuse in the interior fuse panel. Also, listen for a faint 'click' sound from the passenger footwell area when you press the lock switch. If you hear a click, the module is likely receiving the signal and the problem may be with the wiring to the doors or the actuators themselves.
Buying a Used Vehicle Access Control Module
This is the most important section for anyone buying a recycled part. Getting the right module for the S14 240SX is straightforward if you follow these rules.
1. No Programming Required
A replacement Smart Entrance Control Unit does not need to be programmed or flashed to your vehicle. It is a direct plug-and-play part. You can remove the old unit and install a used one without needing a trip to the dealer or a locksmith. This makes a used OEM module an excellent, cost-effective option.
However, if you have a keyless entry model and are replacing the module, you will need to re-program your existing remote fobs to the new unit. This is a simple DIY procedure detailed in the FAQ section below.
2. Match Your Car's Keyless Entry Option
Nissan used two different modules for this generation of 240SX, and they are not interchangeable. You must buy the module that matches your car's factory-installed options.
- For vehicles WITHOUT factory keyless entry: You need part number 28595-70F00.
- For vehicles WITH factory keyless entry (typically SE models): You need part number 28595-70F10.
Warning: Installing a keyless entry module (70F10) in a car that didn't have it from the factory will not automatically grant you keyless entry. The vehicle wiring harness may be different. Always replace your module with the exact same part number.
3. Physical Inspection
When your used part arrives, inspect it before installation. Check the connector pins to ensure they are straight and free of any green or white corrosion, which would indicate water damage. Give the case a gentle shake; there should be no rattling sounds, which could suggest broken internal components.
Cost Comparison
This table breaks down the estimated costs for replacing the Smart Entrance Control Unit. Prices are estimates as of late 2024 and can vary by supplier and location.
| Part Type | Estimated Cost | Notes |
|---|---|---|
| New OEM | $350 - $450+ | Discontinued and extremely difficult to find. |
| New Aftermarket | Not Available | No direct aftermarket replacements are commonly available. |
| Used OEM | $25 - $75 | The most common and cost-effective solution. Widely available from online sellers and salvage yards. |
| Shop Labor | $75 - $150 | Typically 0.5 to 1.0 hour of labor. The module is located behind the passenger kick panel. |
Replacement Guide: Location and Installation
Replacing the Smart Entrance Control Unit is a feasible DIY job for most owners with basic tools.
- Location: The module is located in the passenger-side footwell. It is a small black or gray box mounted to a bracket, positioned above the main Engine Control Unit (ECU).
- Access the Module: You will need to remove the plastic door sill trim and the passenger-side kick panel (the plastic panel in front of the door, by the passenger's feet).
- Remove the ECU (If Necessary): The ECU is the larger metal box. It is often necessary to unbolt the ECU's bracket (typically three 10mm bolts) and move it aside to gain clear access to the smaller Smart Entrance Control Unit located above or behind it.
- Disconnect and Replace: The control unit is held in place by one or two 10mm bolts. Unbolt it, disconnect the single electrical connector, and remove it from the vehicle.
- Installation: Installation is the reverse of removal. Mount the new module, connect the wiring harness, reinstall the ECU and kick panel, and test the functionality of the locks and alarm.
Frequently Asked Questions (FAQ)
Does the 1995-1998 240SX access control module need to be programmed?
No. The module itself is plug-and-play and does not require any programming or dealer intervention. However, if your car has keyless entry, you must re-sync your remote fobs to the replacement module.
How do I program a key fob to the 240SX?
You can program key fobs yourself in under a minute. 1. Get in the car, close and lock all doors using the driver's power lock switch. 2. Insert and completely remove the key from the ignition at least six times within 10 seconds. The hazard lights will flash. 3. Insert the key and turn it to the ACC position. 4. Press any button on the remote. The hazard lights will flash again to confirm programming. 5. To exit programming mode, open the driver's door.
Where is the Smart Entrance Control Unit located?
It is located in the passenger footwell, usually mounted above the larger Engine Control Unit (ECU). You must remove the passenger side kick panel to see and access it.
Can a bad access control module drain my car's battery?
Yes, it is possible. An internal short or a stuck relay within the module could create a parasitic draw that drains the battery when the car is off. If you are experiencing a dead battery and have other symptoms like faulty door locks, the module could be the cause.
My door makes a buzzing noise but won't lock. Is it the control module?
Probably not. A buzzing, whirring, or weak locking motion in a single door is a classic symptom of a failing door lock actuator motor inside that specific door, not the central control module. If both doors stopped working at the exact same time, the module is a more likely culprit.
Technical Specifications
OEM Part Numbers: 28595-70F00 28595-70F10
Controls power locks, factory alarm, dome light timer, and key-in-ignition chime. Operates on the vehicle's 12V DC system.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Nissan 240SX:
- 🛍️ Shop This Part
- Symptoms of a Failing Access Control Module
- Known Issues, Recalls, and TSBs
- Buying a Used Vehicle Access Control Module
- 1. No Programming Required
- 2. Match Your Car's Keyless Entry Option
- 3. Physical Inspection
- Cost Comparison
- Replacement Guide: Location and Installation
- Frequently Asked Questions (FAQ)
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