Explore the whole catalog.
Search every article and filter by category, OBD generation, engine family, chassis and more. Type to reshape the results.
Disabling Cruise Control and Upshift Indicator Lights on P05 ECUs
Eliminate the persistent cruise control or upshift indicator light on modified OBD1 P05 ECUs by removing resistor R135.
Dual Runner Intake Manifold Operation
Understand the operation and tuning principles of Honda dual-runner intake manifolds, including IAB (Intake Air Bypass)...
ECU Nitrous Control Implementation
Implementing ECU-based nitrous solenoid activation to enable dynamic fuel and ignition map switching.
Enabling O2 Sensor Heater Circuitry on OBD1 ECUs
Learn how to enable O2 sensor heater circuitry on OBD1 ECUs like the P05 and P08 by adding the necessary transistor comp...
Exhaust Gas Temperature (EGT) Sensor Overview
An overview of Exhaust Gas Temperature (EGT) sensors and their role in monitoring ignition timing and engine health duri...
Fuel Cut Operation and Theory
A fuel cut disables fuel delivery to the engine, typically triggered by rev limiters, launch control, or boost cut routi...
Honda and Rover Technical Collaboration
Overview of the technical collaboration between Honda and Rover, focusing on shared engine platforms and ECU compatibili...
Honda ECU Identification and Compatibility FAQ
A foundational reference for identifying Honda ECU families, understanding compatibility, and navigating common ECU part...
Honda ECU Microcontroller (MCU) Overview
An overview of microcontroller (MCU) units used in Honda ECUs, defining their role as integrated CPUs with onboard memor...
Honda OBD0 and OBD1 ECU Datalogging Overview
Overview of OBD0 and OBD1 Honda ECU datalogging methods, including serial communication interfaces, historical software,...
JDM P30 D12 Analog-Input Modification
Technical guide for modifying the JDM P30 OBD1 ECU to enable 0-5 V analog signal logging via the D12 input.
Logging an External 0-5 V Sensor via P30 D12
Technical guide for utilizing the undocumented D12 analog input on USDM OBD1 P30 ECUs for 0-5 V external sensor logging.
OBD0 Limp Mode Diagnostics and Operation
An overview of OBD0 Limp Mode, a fail-safe operating state triggered by major ECU malfunctions that limits engine perfor...
OBD2 P5M ECU Automatic to Manual Conversion
Convert an OBD2 P5M ECU from automatic to manual transmission by relocating the 0-ohm SMD resistor.
Oki 8XC154 A5h Opcode Analysis
Technical analysis of the A5h opcode in Oki 8XC154 microcontrollers used in Honda ECUs and methods for standard 8051 com...
One Time Programmable (OTP) EPROM
An overview of One Time Programmable (OTP) EPROMs used in engine control units, detailing their permanent data storage c...
PK3 ECU Technical Reference
Technical overview of the PK3 ECU used in 1990-1991 Honda Prelude B20A DOHC non-VTEC engines.
PM6 Future ECU Code Module
An overview of the PM6 Future code module for Honda PM6 ECUs, providing resources for tuning and firmware development.
Read Only Memory (ROM) Architecture
An overview of Read Only Memory (ROM) architecture and its role in Honda engine control unit (ECU) firmware storage.
Understanding ECU Binary (.bin) Files
An overview of binary (.bin) files used in Honda ECU tuning, explaining their structure as raw 8-bit data containers for...
Understanding the ECU Fuel Map Column Multiplier
The column multiplier is a critical value used in fuel map calculations, located immediately following the fuel map data...
USB-Based ECU Datalogging and Hardware Integration
Technical documentation for USB-based datalogging integration and external hardware interfacing for Honda ECU systems.
Volumetric Efficiency (VE)
Volumetric Efficiency (VE) defines the ratio of air/fuel mixture drawn into the cylinder versus its theoretical maximum...
1991 Honda PM6 ECU Reference
Technical reference for the 1991 Honda PM6 ECU, covering idle target configuration and onboard diagnostic LED troublesho...
1991 PM6 ECU Target Idle Routine Analysis
Technical analysis of the 1991 PM6 ECU target idle routine, including memory address locations and code structure compar...
1991 PM7 ECU Technical Reference
Technical reference for the 1991 PM7 ECU, including idle target configuration and sensor management.
27C256 EPROM Specifications
Technical specifications, pinout diagrams, and speed requirements for the 27C256 EPROM chip used in OBD0 and OBD1 Honda...
28C256 EEPROM Pinout and ECU Compatibility
Technical specifications, pinout mapping, and socket modification instructions for using the 28C256 EEPROM chip in stand...
74HC373 Octal Latch IC
Technical overview of the 74HC373 octal latch IC, commonly used for external ROM interfacing in Honda ECU hardware.
8051 and Oki 66k Carry Bit (C) Reference
An overview of the carry bit (C) functionality within 8051 and Oki 66k architectures, focusing on arithmetic overflow tr...
82C55 Programmable Peripheral Interface
Technical specifications and pinout mapping for the OKI MSM82C55A Programmable Peripheral Interface (PPI) chip used in H...
A143 Transistor Specifications and Replacements
Technical reference for the A143 transistor used in Honda ECU circuits, including specifications and verified component...
Acura Brand History and Overview
Overview of the Acura brand history and its evolution within the Honda automotive ecosystem.
Adding 1-Wire VTEC Control to OBD0 ECUs (PM6)
Hardware modification guide to adding 1-wire VTEC control to OBD0 Honda ECUs by populating unused automatic transmission...
Adding IAB Control to an OBD1 P28 ECU
Hardware modification guide to add Intake Air Bypass (IAB) secondary runner controls to an OBD1 Honda P28 Civic ECU.
Adding Knock Sensor Circuitry to OBD1 ECUs
Step-by-step hardware guide for adding a knock sensor circuit to non-equipped Honda OBD1 ECUs using specific component m...
Air-Fuel Ratio (AFR) Guide for Honda Tuning
An introduction to Air-Fuel Ratio (AFR) in internal combustion engines, explaining stoichiometric targets, rich vs. lean...
Application Programming Interface (API) Reference
An Application Programming Interface (API) is a set of functions within a library or DLL that allows software to perform...
ASM662 Assembler and Disassembler
ASM662 is an assembler and disassembler tool for Oki 66201, 66207, 66301, and NEC 66911 microcontrollers used in various...
Atmospheric Pressure (PA) Sensor Reference
The atmospheric pressure (PA) sensor measures ambient air pressure to adjust fuel mixtures for altitude and weather-rela...
Atmospheric Pressure (PA) Sensor Technical Reference
Technical guide to the Atmospheric Pressure (PA) sensor in Honda ECUs, explaining its role in altitude compensation and...
Australian Domestic Market (OzDM) Vehicle Specifications
Technical overview of Australian Domestic Market (OzDM) Honda vehicle specifications and ECU configurations.
Automatic to Manual Transmission ECU Conversion
Convert an automatic transmission ECU to manual transmission operation by removing specific resistors and adding a jumpe...
Automatic Transmission Lockup Solenoid
An overview of the Automatic Transmission Lockup Solenoid function, ECU pinout, and common repurposing for OBD0 Honda ve...
Back Links Functionality
An overview of the Back Links functionality used to identify pages that link to or reference the current technical artic...
Batronix USB Programmer Technical Guide
Technical overview and operational guidelines for using the Batronix USB Programmer to read and write ECU EPROM and Flas...
C144 NPN Switching Transistor
Technical specifications and replacement guide for the C144 NPN switching transistor used in Honda ECU circuits.
C2785 NPN Switching Transistor
Technical specifications and compatible replacements for the C2785 high-speed NPN switching transistor used in Honda ECU...
Camshaft Profile Fundamentals
An overview of camshaft profiles, defining the fundamental measurements of cam lift, duration, and overlap for internal...
check8 8-Bit ROM Checksum Utility
A command-line utility for verifying and correcting 8-bit ROM checksums during firmware compilation.
Chipping 1988-1989 OBD0 ECUs
Technical procedures for socketing and chipping 1988-1989 OBD0 Honda and Acura ECUs equipped with internal-ROM OKI M83C1...
Chipping OBD1 Small-Case ECUs
Step-by-step instructions for socketing and chipping small-case Honda OBD1 ECUs, commonly found in JDM and some European...
Chipping OBD2 Honda ECUs (OKI 66507 / 66P507)
Hardware guide for chipping OBD2 Honda ECUs by replacing the OKI 66507 processor with a programmed 66P507 OTP microcontr...
Chipping the JDM OBD1 P30 ECU
Hardware modification guide for socketing, chipping, and converting JDM square-case OBD1 P30 ECUs to manual transmission...
Clamping Diode Installation and Selection
Learn how to protect sensitive ECU circuitry from voltage spikes caused by inductive loads like solenoids using a clampi...
Contributing to Hondabase Documentation
Learn how to contribute to the Hondabase knowledge base by utilizing the Edit Text feature available on all technical do...
Converting Intel HEX Files to Binary (BIN)
Learn how to convert Intel HEX files to binary (BIN) format for ECU tuning and ROM programming using the hex2bin utility...
Crankshaft Position (CKP) Sensor Operation
Technical overview of the Crankshaft Position (CKP) sensor, its function in engine management, and its integration withi...
Crome JavaScript Scripting API
Technical reference for the legacy Crome ROM editor JavaScript API used for developing scripts, ROM handlers, and plug-i...
Crome ROM Editor Overview
Crome is a ROM editor for Honda ECUs that supports JavaScript-based scripting for custom feature implementation and exte...
Found a gap or an error? Sign in with Discord to suggest an edit (reviewed before it goes live), or join the community on Discord and GitHub.
Join the Discord →