2000-2001 Nissan Altima Body Control Module: NATS Immobilizer and Reprogramming Explained
This guide covers the common failures, replacement costs, and critical reprogramming steps for the Body Control Module (BCM) in the 2000-2001 Nissan Altima.
- Replacing the BCM requires mandatory reprogramming by a Nissan dealer or specialist due to the NATS immobilizer system.
- A 'crank-no-start' condition with a solid red security light is the most definitive symptom of a BCM/NATS failure.
- The correct name for this part is the 'Smart Entrance Control Unit', and you must match part numbers exactly when buying a replacement.
- Before replacing the BCM, always check all related fuses and confirm the battery and alternator are in good condition.
Understanding the BCM and NATS Immobilizer Link
The single most important thing to understand about the Body Control Module (BCM) in a 2000-2001 Nissan Altima is its connection to the Nissan Anti-Theft System (NATS). The BCM, the Engine Control Module (ECM), and the transponder chip inside your ignition key are all electronically linked. For the engine to start, all three components must recognize each other. If you replace the BCM, this link is broken, and the NATS immobilizer will prevent the engine from starting, even with your original key.
Warning: After installing a replacement BCM, the vehicle will not start until it is reprogrammed by a Nissan dealership or a qualified automotive locksmith with a Nissan-specific CONSULT-II scan tool. This is not an optional step.
Symptoms of a Failing Body Control Module
BCM failure often causes a variety of strange and seemingly unrelated electrical problems. 🎬 Watch: 5 common symptoms of a failing BCM and how to check it. Because the BCM controls so many different systems, you may experience one or more of the following issues:
Common Electrical Glitches
- Power Accessories Malfunction: Power windows, power door locks, or power mirrors may stop working entirely or work only intermittently.
- Lighting Problems: Interior dome lights may not turn on or off correctly, or exterior lights may flicker or fail to operate.
- Keyless Entry Failure: The remote fob may suddenly stop locking or unlocking the doors.
- Parasitic Battery Drain: A faulty BCM can fail to shut down a circuit, causing a slow drain that kills the battery overnight.
Starting and Security Issues
- Crank, No Start with Solid Security Light: This is the most definitive symptom of a NATS-related BCM failure. The engine will turn over but will not fire up, and the small red security light on the dashboard will stay lit continuously when the key is in the 'ON' position.
- Alarm System Malfunctions: The factory alarm may trigger randomly for no reason or may not arm when you lock the doors.
Diagnosing the Issue
Before condemning the BCM, it's important to rule out simpler problems:
- Check Fuses: Inspect all fuses related to the BCM, interior electronics, and ignition systems. A single blown fuse can mimic BCM failure.
- Test the Battery and Alternator: A weak or failing battery can cause widespread electrical issues and communication errors between modules. Ensure your battery is fully charged and the charging system is working correctly.
- Inspect Grounds: A loose or corroded ground wire for the BCM can cause erratic behavior.
- Consider Other Common Failures: The 2000-2001 Altima was subject to a recall for faulty crankshaft and camshaft position sensors, which can also cause a 'crank, no start' condition. However, this issue typically does not cause the other electrical body-related symptoms that a failing BCM does.
Pro Tip: If you are experiencing a 'crank, no start' issue, pay close attention to the security light on the dashboard. If it is solid red with the key on, the problem is almost certainly related to the NATS immobilizer system, 🎬 See this detailed wiring diagram for the Nissan immobilizer system. with the BCM being a primary suspect.
Buying a Used Body Control Module
Given that new OEM modules are often discontinued and expensive, a used OEM module is a very common and cost-effective repair. Here’s what you need to know:
- Match the Part Number Exactly: There are several different BCM part numbers for this Altima. You must find a replacement with a part number that is identical to the one on your original module. Common part numbers include 28595-0Z801, 28595-0Z810, and 28595-9B900.
- Inspect for Damage: Do not buy a module with any signs of water damage, corrosion on the pins, or a burnt smell. The BCM is located inside the cabin, typically in the center of the dashboard, behind the radio/climate control area.
- Budget for Programming: The cost of the used module is only part of the total expense. You MUST factor in the cost of having it programmed at a dealership or specialist shop. This can range from $100 to $250.
- Why Used OEM is a Good Choice: For an electronic part like this, a used original Nissan part that has been tested is often more reliable than a new, unproven aftermarket unit. As long as it is programmed correctly, it will function exactly as the original did.
Cost Breakdown for Replacement
The total cost can vary significantly based on the price of the part and local labor rates.
| Item | Estimated Cost |
|---|---|
| New OEM Module | $450 - $650+ (if available) |
| Remanufactured Module | $200 - $350 |
| Used OEM Module | $40 - $100 |
| Shop Labor (Physical Swap) | $100 - $150 (approx. 1 hour) |
| Shop Labor (Reprogramming) | $100 - $250 (dealer/specialist service) |
| Total Estimated Cost (with Used OEM Part) | $240 - $500 |
Frequently Asked Questions (FAQ)
Will my car start after I install a used BCM?
No. The car will crank but will not start due to the NATS immobilizer until the replacement BCM is programmed to the vehicle's keys and ECM. This requires a special scan tool.
Can a locksmith program the new BCM instead of the dealer?
Some specialized automotive locksmiths have the advanced, dealer-level equipment (like a Nissan CONSULT tool) required to perform this service. However, many do not. You must call and confirm they can specifically program a replacement BCM for a 2000-2001 Nissan Altima before committing.
Is the Body Control Module the same as the Engine Control Module (ECM)?
No. They are separate computers. The ECM (also called the ECU) controls engine functions like fuel injection and ignition timing. The BCM controls body functions like lights, windows, and locks. They communicate with each other, especially for the security system, but they are not the same part.
Can I just unplug my BCM to 'reset' it?
While disconnecting the battery or the module may temporarily clear a minor glitch, it will not fix an internally failed BCM. 🎬 Watch: How to test, fix, and reset a bad BCM. If the module has failed, it will need to be replaced and reprogrammed.
Helpful Videos
Technical Specifications
OEM Part Numbers: 28595-0Z801 28595-0Z800 28595-0Z810 28595-9B900
Location: Center of dashboard, behind radio/climate controls. Controls: Power locks, windows, interior/exterior lights, keyless entry, rear defogger, warning chimes, NATS immobilizer.
We Have This Part in Stock
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 Altima:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding the BCM and NATS Immobilizer Link
- Symptoms of a Failing Body Control Module
- Common Electrical Glitches
- Starting and Security Issues
- Diagnosing the Issue
- Buying a Used Body Control Module
- Cost Breakdown for Replacement
- Frequently Asked Questions (FAQ)
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