RX-8 NVRAM & KAM Reset Guide

How your ECU remembers, and when to make it forget.

🔧 What are NVRAM and KAM?

The RX-8’s PCM (Powertrain Control Module), like any modern ECU, stores key data even when the car is off. One of these storage systems is NVRAM (Non-Volatile Random Access Memory).

In the RX-8, NVRAM holds the Long-Term Fuel Trim (LTFT) data, which directly affects fuel mixture adjustments.

The Keep Alive Memory (KAM) stores sensor behavior patterns (like those from the MAF sensor) and—more uniquely—the learned profile of your engine’s eccentric shaft (e-shaft) plate. This data reflects how your specific engine spins, making each RX-8’s stored memory profile slightly unique. It’s part of what allows the ECU to “learn” and adapt to your driving over time.

If your RX-8 throws lean or rich mixture codes, or your fuel trims reach extreme values (±25%), resetting this memory can help return the ECU to a known baseline.

Note: Disconnecting the battery won’t reset this data. It requires a deliberate reset procedure.

🧠 Why Reset NVRAM?

You should only reset the NVRAM under specific conditions:

• You replaced the engine or e-shaft pulley

• You changed pulleys or components affecting the e-shaft sensor

• You installed a new PCM / ECU

• You repaired a misfire but codes persist

• You worked on electrical or sensor wiring and now have odd DTCs

Resetting NVRAM can help eliminate ghost errors or mismatches between mechanical parts and stored memory.

🔄 NVRAM Reset Procedure

For Series 1 (2004–2008)

1. Turn ignition to ON, but do not start the engine.

2. Within 8 seconds, press the brake pedal at least 20 times.

Confirmation:

• Vehicles after VIN 40132647 (manual) or 40132607 (auto) — or with PCM updated to "L" calibration or later — will show a gauge movement:
  ➤ The oil pressure gauge will shift slightly right of center (toward “H”).

• For other vehicles:
  ➤ Check if trip meter, clock, and radio presets were reset. If yes, NVRAM was cleared.

For Series 2/3 (2009–2011)

1. Record custom radio presets (FM/AM/SAT).

2. Disconnect negative battery terminal for at least 1 minute.

3. With the battery still disconnected, press the brake pedal once.

4. Reconnect battery.

5. If equipped with DSC:
   ➤ Perform steering angle sensor reset:
   Turn steering fully right, then fully left.

6. Re-enter radio presets.

7. Re-initialize power windows:
   Open fully, then close fully once.

⚠️ Important Tip:

Even though the process sounds simple, be cautious during electrical work or when changing drivetrain components. NVRAM mismatches can cause obscure codes or rough driving behavior. When in doubt, reset.

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