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Pinouts OBD2b


EDM P2Y (D15Z6)



On this page the OBD2b sheme from the EDM (Europen Domestic Market) D15Z6 also known as the 115 bhp VTEC-E is shown. 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. The NEP connections marked in red deserves special attention.


 OBD2b pinout for D15Z6 engine



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

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

ECT -    Engine coolant temperature

EGRL - Unknown function (probably related to EGR)

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

ESOL - Unknown function (probably OBD1 EGR)

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

FLR -    Fuel relay

IACV - Idle air control valve, controls the 2 wire type IACV valve

IAT -     Intake air temperature

ICM -    Ignition pulses, 1 is always present, 2 can be ignored

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)

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

LG -      Ground for battery circuit

MAP -   Manifold absolute pressure

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

NEP -   Signal to engine speedometer

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

PG -     Ground for battery circuit

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

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

VTS -    VTEC solenoid


OBD1 conversions are very straightforward even using only the shemes provided in the pinout section on my site. However the NEP signal needs some attention. In OBD2b this wire is a rpm signal send by the ECU directly towards the rpm gauge in the cockpit. However with al other OBD types the gauge gets its signal not from the ECU, but from the distributor. For all other OBD types (and MPFi) there are 9 wires on the distributor, OBD2b has only 8 wires. The blue one misses on OBD2b and is used by the other OBD types for the signal towards the rpm gauge. The solution when installing an OBD1 ECU is simple, connect NEP to ICM.

Besides that 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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