PR7 OBD1 ECU Technical Reference
Technical hardware overview and specifications for the PR7 OBD1 ECU used in 1991–1994 Acura NSX models.
The PR7 ECU is the factory engine control unit utilized in 1991â1994 Acura NSX (NA1) vehicles. It operates on the OBD1 communication standard and manages the C30A engine platform.
Hardware Overview
The PR7 utilizes a unique architecture compared to standard B-series or D-series OBD1 ECUs.
Important
While the PR7 shares the OBD1 connector physical interface, the internal pinout and logic are specific to the NSX C30A engine. Do not attempt to swap this ECU into other Honda/Acura chassis without verifying pin-for-pin compatibility.
Technical Specifications
| Feature | Specification |
|---|---|
| Generation | OBD1 |
| Vehicle Application | 1991â1994 Acura NSX |
| Engine | C30A |
| Transmission | Manual / Automatic (Variant dependent) |
Component Identification
The PR7 board layout is optimized for the dual-bank ignition system required by the NSX V6 engine.
Diagnostics
Use the following tool to reference error codes associated with the PR7 ECU and the C30A engine management system.
Wiring Reference
For specific sensor integration, refer to the standard OBD1 wiring conventions.
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Tip
When performing diagnostics on the PR7, ensure the main relay is functioning correctly, as NSX-specific electrical loads can cause intermittent voltage drops at the ECU power pins.