Honda ECU & PCM Modules – 37820, Keihin and Bosch

Honda engine control units – ECU identification by Honda and manufacturer part number

A Honda engine control unit (ECU), also known as an ECM, PCM or engine computer depending on the vehicle and documentation, manages engine operation and communicates with other electronic systems. Depending on the engine and control-unit generation, the module may manage fuel injection, ignition, electronic throttle operation and other engine-related functions.

When replacing a Honda ECU, however, the most important step is identifying the exact electronic module fitted to the vehicle. Honda has used many different control-unit versions across Civic, Accord, Jazz, CR-V, Prelude and older vehicle generations. Modules that look almost identical can contain different hardware, software, calibration or vehicle-specific security information.

Honda 37820 ECU numbers – the key identification family

One of the most characteristic number groups in Honda engine electronics is the 37820... family. It appears repeatedly throughout the current Auto24Parts Honda ECU catalogue.

Examples include:

• 37820-R5Z-G74,
• 37820-PDT-E12,
• 37820-PNE-E01,
• 37820-P06-G00,
• 37820-P5R-G31,
• 37820-P5R-G81,
• 37820-PDA-E11,
• 37820-P45-G21,
• 37820-P45-G30,
• 37820-P45-G31,
• 37820-PDC-E12.

The shared 37820 section does not mean that these ECUs are interchangeable. The complete letters and numbers following 37820 must also be compared.

Honda ECU numbers with and without hyphens

Honda engine control-unit references frequently appear in both formatted and compact versions. For example:

• 37820-R5Z-G74 / 37820R5ZG74,
• 37820-PDT-E12 / 37820PDTE12,
• 37820-P5R-G31 / 37820P5RG31,
• 37820-PMH-E11 / 37820PMHE11,
• 37820-RB0-E14 / 37820RB0E14,
• 37820-PL2-G12 / 37820PL2G12,
• 37820-P11-G01 / 37820P11G01.

Both formats are useful when searching for a replacement ECU because workshops, online catalogues and module labels may record the same reference differently.

Honda 0281032864 / 37820-R5Z-G74

A current Bosch application is the Honda ECU Bosch 0281032864 / 37820-R5Z-G74 / 37820R5ZG74.

This module provides a good example of two numbering systems appearing on the same engine computer: 0281032864 identifies the Bosch reference while 37820-R5Z-G74 is the Honda-style number.

For precise identification, both references should be compared with the original ECU label rather than selecting the module only from its housing or connector layout.

Honda Civic – 37820-PDT-E12 / 673683-0711

For Honda Civic, one current product is the Honda Civic ECU 37820-PDT-E12 / 37820PDTE12 / 673683-0711 / 6736830711.

The Honda number can be found in formatted and compact forms, while 673683-0711 provides an additional electronics reference.

Using all available numbers helps distinguish this ECU from the many other Civic engine control modules currently present in the catalogue.

Honda Accord 1.8 – 37820-P5R-G31 / R3C

One Accord application is the Honda Accord 1.8 ECU 37820-P5R-G31 / 37820P5RG31 / R3C.

The complete suffix P5R-G31 is important. Another Accord control unit in the catalogue carries 37820-P5R-G81, while other Accord applications use P45, PDA, PDC and P39 references.

This makes “Honda Accord ECU” a useful initial search phrase, but not a sufficient compatibility check.

Honda Accord – several separate 37820 ECU references

Accord is one of the strongest model groups in the current Honda category. Examples include:

• 37820-P5R-G31 / R3C,
• 37820-P5R-G81,
• 37820-PDA-E11 / JW,
• 37820-P45-G21,
• 37820-P45-G30 / 53A,
• 37820-P45-G31 / 53A,
• 37820-PDC-E12,
• 37820-P39-N01 / 0N6,
• 37820-PDC-E51 / 582916-9706.

The differences between G21, G30 and G31 or between P5R, PDA and PDC references should not be ignored. The full module label should always be checked.

Honda Civic – one model, many ECU generations

Civic is another major application cluster in the current Honda range. Available modules use many different Honda and manufacturer references, including:

• 37820-PDT-E12 / 673683-0711,
• 0281012660 / 9S131312050077,
• 37820-P1J-G11 / XK,
• 37820-P9L-E11 / J2,
• 37820-PMH-E11 / LT,
• 37820-RSA-G33,
• 37700P01G01,
• 37820-P04-G02,
• 37820-P04-G03,
• 37820-P1G-E00 / 010826-5627,
• 37820-P3Y-G01,
• 37820-PM5-X080,
• 37820-RSA-G01,
• 0281013406.

These examples demonstrate why a replacement Civic ECU should not be selected only by generation, engine capacity or external appearance.

Honda Civic 1.6 – 37820-PMH-E11 / LT

A current Civic 1.6 module is the Honda Civic ECU 37820-PMH-E11 / 37820PMHE11 / LT.

The short LT designation provides additional identification alongside the complete Honda number. All markings visible on the original module should be retained when searching for the correct replacement.

Honda Civic – Bosch 0281013406

The Honda catalogue is not limited to traditional 37820-only references. A current example is the Honda Civic Bosch ECU 0281013406.

This module uses a Bosch 0281... manufacturer number, demonstrating that electronics supplier references can be particularly important on some Honda applications.

Honda Jazz 1.3 – Keihin 37820-RB0-E14

Keihin is another important electronics manufacturer represented in the Honda category. One current example is the Honda Jazz 1.3 Keihin ECU 37820-RB0-E14 / 37820RB0E14 / F9.

This module combines the Honda reference with the additional F9 designation. The product demonstrates why a Honda ECU catalogue should not be built exclusively around Bosch numbers.

Honda CR-V 2.0 16V – 37820-P3F-G01

The current category also includes a Honda CR-V 2.0 16V engine control unit identified as 37820-P3F-G01 / 37820P3FG01 / TH.

The model and engine description help narrow the search, but the complete 37820 reference remains the primary identification point.

Honda Prelude – 37820-P11-G01

For Honda Prelude, one available module is the Honda Prelude ECU 37820-P11-G01 / 37820P11G01 / 1GA.

Other Prelude products in the current category use different numbers, including 37700-PKI-771 and 37820-P5N-G02. The model name alone therefore cannot confirm compatibility.

Honda Legend / Rover – 37820-PL2-G12 / CY-EH6915A

Selected older Honda electronics also appear in shared Honda / Rover applications. One example is the Honda Legend / Rover ECU 37820-PL2-G12 / 37820PL2G12 / CY-EH6915A.

The shared Honda / Rover application should not be interpreted as universal interchangeability between the two brands. The complete reference and vehicle application still need to be checked.

Honda and Rover shared ECU applications

The current Honda catalogue contains more than one product connected with Honda / Rover applications, including:

• 37820-PL2-G12 / CY-EH6915A – Honda Legend / Rover,
• 37820-PP4-G51 / TB – Honda / Rover 1.6.

These shared applications are useful for exact-number searches, but compatibility should always be confirmed from the original ECU label.

Keihin and Bosch Honda engine control units

The current Honda category includes both Keihin and Bosch control units together with other original Honda modules.

Bosch references visible in the catalogue include numbers such as 0281032864, 0281012660 and 0281013406, while the Honda Jazz example 37820-RB0-E14 is identified as a Keihin unit.

The electronics manufacturer is useful for narrowing the search, but manufacturer name alone does not confirm compatibility.

Other Bosch electronic modules can be found in the Bosch automotive electronics section.

Why every letter in a Honda 37820 number matters

Honda references often have a structured suffix after the 37820 prefix. For example:

• 37820-P45-G21,
• 37820-P45-G30,
• 37820-P45-G31.

These numbers look very similar, but they should be treated as separate references unless compatibility has been specifically confirmed.

The same applies to:

• 37820-P5R-G31 versus 37820-P5R-G81,
• 37820-RSA-G01 versus 37820-RSA-G33,
• 37820-P04-G02 versus 37820-P04-G03.

When searching for a Honda engine computer, do not shorten the reference by removing the final letters or digits.

Used / locked Honda ECU

A standard used / locked Honda engine control unit may retain vehicle-specific and security-related information from the vehicle in which it was previously installed.

Depending on the ECU and vehicle generation, further electronic preparation or programming may therefore be required before the replacement module can operate correctly in another vehicle.

Honda ECU ready for programming

Selected Honda products in the Auto24Parts catalogue are available in locked and ready-for-programming variants. The exact preparation available depends on the control unit and vehicle application.

After installation, programming, adaptation or immobiliser-related synchronisation may be required depending on the specific Honda ECU and how the replacement module has been prepared.

See the ECU preparation options page for more information.

VIRGIN Honda ECU

For selected Honda control units, a module may be reset or prepared for subsequent adaptation to another vehicle. This type of preparation may be described as VIRGIN.

The exact procedure depends on the ECU and vehicle generation. VIRGIN should therefore not automatically be interpreted as Plug & Play unless the specific product description confirms this.

Honda ECU cloning

For selected compatible control units, Honda ECU cloning may be another preparation method. If the required information can be correctly read from the original module, relevant data may be transferred to a compatible replacement ECU.

Depending on the ECU design, this can involve memory content, software, configuration and security-related information.

The possibility of cloning depends on the ECU type and condition of the original module. If the required data cannot be recovered correctly, another preparation method may be necessary.

Honda immobiliser and ECU replacement

Depending on the Honda model and electronic architecture, replacement of a used engine control unit may involve the vehicle security system. A used ECU should therefore not automatically be expected to start another vehicle immediately after installation.

The required procedure depends on the exact control unit, vehicle and preparation method. Programming or security-related adaptation may be necessary in selected applications.

Common symptoms that may indicate a Honda ECU problem

A defective engine control unit can produce different symptoms, but similar problems may also be caused by sensors, wiring, actuators, power-supply faults or other electronic systems.

• engine does not start,
• no diagnostic communication with the ECU,
• engine stalls or is difficult to restart,
• limp mode or reduced engine power,
• injector or ignition-control faults,
• incorrect throttle response,
• repeated diagnostic trouble codes,
• communication faults between vehicle modules,
• internal ECU memory or electronics faults.

Before replacing the engine control unit, check battery voltage, ECU power supply, ground connections, fuses, relays, connectors and wiring. A diagnostic trouble code alone does not prove that the ECU itself is defective.

Honda engine control units by exact part number

Searching by the complete Honda and electronics manufacturer references is one of the most effective ways to locate the correct replacement ECU:

• 0281032864 / 37820-R5Z-G74 / 37820R5ZG74 – Honda Bosch ECU
• 37820-PDT-E12 / 37820PDTE12 / 673683-0711 – Honda Civic ECU
• 37820-P5R-G31 / 37820P5RG31 / R3C – Honda Accord 1.8 ECU
• 0281013406 – Honda Civic Bosch ECU
• 37820-PMH-E11 / 37820PMHE11 / LT – Honda Civic 1.6 ECU
• 37820-RB0-E14 / 37820RB0E14 / F9 – Honda Jazz 1.3 Keihin ECU
• 37820-PL2-G12 / CY-EH6915A – Honda Legend / Rover ECU
• 37820-P11-G01 / 37820P11G01 / 1GA – Honda Prelude ECU

How to check Honda ECU compatibility before ordering

Take a clear photo of the complete original ECU label. The Honda 37820 or other OEM reference, Bosch, Keihin or other electronics manufacturer number and any additional hardware, software or calibration identifiers should all be readable.

If you need help identifying the correct replacement module, contact Auto24Parts and send the photo together with the Honda model, model year, engine capacity, power output and engine version.

For other vehicle makes, browse the complete engine control unit catalogue. Other Honda electronic components can also be found in the Honda ABS pump category.

Before ordering, you can also review our How to Buy guide, Shipping & Delivery information and Returns, Warranty & Complaints conditions.

FAQ – Honda ECU and Engine Control Units