Pinouts OBD2a

 

EDM/USDM/JDM (D15Z6/D16xx, B16xx, B18xx)

 

 

On this page the OBD2a scheme from a variety of OBD2a cars is presented. Some connections are different from car to car. Others are less important (read: not occurring in OBD1 cars). Both types of connections are marked grey.

 

 

 OBD2a pinout for various engines

 

Nomenclature:

ACC -   A/C relay

ACS -   A/C switch

ALTC -  Alternator relay, for control purposes, not present on all ECU’s

ALTF -  Alternator switch

BKSW- Brake switch, for control purposes, not present on all ECU’s

CKF -   Crankshaft speed, (P)ulse or (M)ass, gives 12 pulses by LED during each crank shaft rotation, not present on all ECU’s

CKP -   Crankshaft position, (P)ulse or (M)ass, gives several pulses (~20?) during each cam shaft rotation

CYP -   Cylinder position, (P)ulse or (M)ass, gives one pulse during each cam shaft rotation

DLC -    Diagnostic connector, communication signal to the 3 wire connector next to the SCS connector

ECO -   ECONOMO light, not present on all ECU’s

ECT -    Engine coolant temperature

EGR -   Unknown function (probably related to EGR), not present on all ECU’s

ELD -    Electric load detection, not present on all ECU’s

ESOL - Unknown function (probably OBD1 EGR), not present on all ECU’s

FANC - Fan relay, for control purposes, not present on all ECU’s

FAS -   Completely unknown function to me

FLR -    Fuel relay

IAB -     Secondary butterfly valve (B18C4)

IACV - Idle air control valve, controls the 2 wire type IACV valve or in case of N and P controls the 3 wire type IACV

IAT -     Intake air temperature

ICM -    Ignition pulses, 1 is always present

IGP -    Battery feed, only active when key is turned

IMO. -   Checks IMO code of the key and activates FLR if correct

INJ -     Injector, the number refers to the cylinder used (1 is on the side with the belts)

LG -      Ground for battery circuit

MAP -   Manifold absolute pressure

MIL -     Motor indication light, this one gives the control engine light (CEL) signal

PCS -   Control solenoid, this one is for the small black cylindric valve on the back of the IM

PG -     Ground for battery circuit

PO2H - Primary oxygen heater switch, not present on all ECU’s

PO2S - Primary oxygen sensor signal

PSP. -  Power steering switch, not present on all ECU’s

SCS -   Service connector switch, checks if the SCS connector is hot wired (for reading engine error codes)

SG -     Ground for 5V circuit, 1 is for the MAP sensor, 2 is for the other sensors

SO2H - Secondary oxygen heater switch, not present on all ECU’s, position not certain

SO2S - Secondary oxygen sensor signal, not present on all ECU’s, position not certain

STS -    Starter switch

TDC -    Top dead centre, (P)ulse or (M)ass, gives four pulses during each cam shaft rotation

TPS -    Throttle position signal

VBU -   Back up battery feed, always active (unless battery is removed)

VCC -   5V feed, 1 is for the MAP sensor, 2 is for the other sensors

VSS -   Vehicle speed sensor

VTM -   Oil pressure switch, not present on all ECU’s

VTS -    VTEC solenoid

VTSB - Secondary VTEC solenoid for 3-stage VTEC engines (D15B)

 

Many OBD1 ECU’s use a VTM or VTPS (VTEC Pressure Switch) to monitor if there is enough oil pressure to engage VTEC safely. A few OBD1 engines and many OBD2 engines lack this VTM sensor. This can be omitted by splitsing the VTS wire and connecting the 2 end to VTM. This will let the ECU think there is enough oil pressure.

 

Please, send any questions and/or remarks to me.

 

Dodo Bizar

 

 

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