Identifying your ECU
To identify your ECU you will need to know its generation, part number
and possibly its ROM number.
The ECU can be located in several places: under a metal plate in the
passenger's footwell (models up to 91), in the passenger's footwell behind
a plastic panel (models 92-99) or by the driver's footwell under a plastic
panel (some models 2000+)
The computer is connected via three connectors that pull out when a
plastic clip is pressed. Remove the computer, and with a philips
screwdriver remove the metal lid from the top of the computer. There may
be small daughter circuit board covering some of the main circuitry.
Unscrew this and lift it out of the way.
Honda ECUs run in generations, which use different connectors.
Below is a stack of ECUs running from the newest generation at the top to
the oldest generation at the bottom.
OBD2B (left 3 plugs used)
OBD0 (JDM PR3 and PWO)
ECU Part Numbers
All Honda ECUs have a part number which is located on the side of the
ECU and inside the ECU on the connector. e.g. 37820-P72-A01
The part number consists of three components:
- Honda's part number for ECU, which is always 37820
- Three characters (which are loosely related to the model of
car/engine). e.g P72
- Three characters (which are the revision of the ECU) e.g. A01 or G52
The middle three characters are the most useful to identify what the
ECU is. Different generation ECUs may use the same characters. e.g.
a P72 OBD I ECU is different from a P72 OBD II ECU. Here is a list of
The last 3
characters are broken down into 3 parts. "A" generally is used for US ECUs. "G"
is European, and "J" is Japanese. There are other versions of this, but you get
the idea. The second digit "0" typically means manual transmission, where a "5"
means automatic transmission, and the last digit "1" is the version number.
- PG7 : 86-89 Integra (86-87 vac advance, 88-89 electronic advance)
- PM5 : 88-91 Civic/CRX DX
- PM6 : 88-91 Civic/CRX SOHC Si
- PM7 : 89-91 DOHC ZC (JDM 'EF' ECU)
- PM8 : 88-91 CRX HF
- PR2 : 89-91 ZC (Euro)
- PR3 : 89-91 JDM B16A EF8/9
- PR3 -J00 or J51 : 92 JDM Integra B16A EF8/9
- PW0 : 89-91 JDM B16A EF8/9 DA6-XSi
- PR4 : 90-91 Integra LS/GS
- PS9 : 88-91 4 door Civic EX Auto
- P05 : 92-95 OBD-1 Civic CX
- P06 : 92-95 OBD-1 Civic DX
- P07 : 92-95 OBD-1 Civic VX
- P08 : 92-95 OBD-1 Civic D15 JDM
- P0A : 94-95 OBD-1 Accord EX
- P13 : 93-95 OBD-1 Prelude Vtec
- P14 : 93-95 OBD-1 Prelude Si (non Vtec)
- P27 : 92-95 OBD-1 EG JDM Civic 1600 sohc
- P28 : 92-95 OBD-1 Civic Si/Ex
- P30 : 92-95 OBD-1 DelSol DOHC Vtec Si/EG SiR
- P54-G31 : 1997 Honda Accord 1.8 LS
- P61 : 92-93 OBD-1 Integra GSR
- P72 : 94-95 OBD-1 Integra GSR
- P72 : 96-00 OBD-2 Integra GSR
- P73 : 96-00 OBD-2 Integra Type-R (JDM & USDM)
- P74/75: 92-95 OBD-1 Integra LS/GS
- P75 : 96-00 OBD-2 Integra LS/GS
- P2N : 96+ OBD-2 Civic HX Coupe
- P2P : 96+ OBD-2 Civic EX Coupe
- P2E : 96+ OBD-2 Civic DX Coupe
- P2M : 96+ OBD-2 NZ Civic SOHC VTEC
- P2T : 99+ OBD-? Civic Si Coupe
- P5P : 97-00 OBD-2 Prelude Type-S (JDM ECU)
- PBA : 97+ US Acura 1.6EL
- PCT : 98+ JDM ITR / CTR
- PCX : 99+ OBD-? S2000
ECU ROM Numbers
As further identification Honda ECUs have a software revision number
inside the ECU. This is usually a two or three digit number stamped
on the 28 pin ROM, or main processor. Accord and Prelude ECUs can use a
letter and number code.