LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 2004 >> Civic GX >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Fuel System & Emissions System (GX) (Supplement) >> System Description >> Electronic Control System >> PCM Inputs and Outputs at Connector E (31P)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

PCM Inputs and Outputs at Connector E (31P)

Fig 1: Identifying Connector E (31P) Terminals
G04535993Courtesy of AMERICAN HONDA MOTOR CO., INC.
NOTE: Standard battery voltage is 12 V.
CONNECTOR E (31P) TERMINALS REFERENCE

Terminal number Wire color Terminal name Description Signal
1 GRN/YEL IMOFPR (IMMOBILIZER FUEL PUMP RELAY) Drives PGM-FI main relay 2 0 V for 2 seconds after turning ignition switch ON (II), then battery voltage
3 BRN/YEL LG3 (LOGIC GROUND) Ground for the PCM control circuit Less than 1.0 V at all times
4 PNK SG3 (SENSOR GROUND) Sensor ground Less than 1.0 V at all times
5 YEL/BLU VCC3 (SENSOR VOLTAGE) Provides sensor voltage With ignition switch ON (II): about 5 V
With ignition switch OFF: about 0 V
7 RED/YEL MRLY (PGM-FI MAIN RELAY) Drives PGM-FI main relay 1 power source for the DTC memory With ignition switch ON (II): about 0 V
With ignition switch OFF: battery voltage
9 YEL/BLK IG1 (IGNITION SIGNAL) Detects ignition signal With ignition switch ON (II): battery voltage
With ignition switch OFF: about 0 V
12 BLU/ORN CCS (CRUISE CONTROL SIGNAL) Detects cruise control signal When cruise control is used and accelerator pedal released: pulses
13 WHT/BLU ILU (INTERLOCK CONTROL UNIT) Drives interlock control unit With ignition switch ON (II) and brake pedal pressed: battery voltage
14 LT GRN PF2 (FUEL PRESSURE SENSOR) Detects fuel pressure sensor signal At idle: 2.3-3.0 V (depending on engine speed)
15 GRN/RED ELD (ELECTRICAL LOAD DETECTOR (ELD)) Detects ELD signal With ignition switch ON (II): about 0.1-4.8 V (depending on electrical load)
16 LT GRN/BLK PSPSW (POWER STEERING PRESSURE SWITCH SIGNAL) Detects PSP switch signal At idle with steering wheel in straight ahead position: 0 V
At idle with steering wheel at full lock: battery voltage
17 BLU/RED TF2 (FUEL TEMPERATURE SENSOR) Detects fuel temperature sensor signal With ignition switch ON (II): about 0.1-4.8 V (depending on fuel temperature)
18 RED ACC (A/C CLUTCH RELAY) Drives A/C clutch relay With compressor ON: about 0 V
With compressor OFF: battery voltage
19 ORN PF0 (FUEL TANK PRESSURE (FTP) SENSOR) Detects FTP sensor signal With ignition switch ON (II): about 0.5-4.5 V (depending on the amount of fuel)
20 GRN STSWC (STARTER SWITCH SIGNAL CONTROL) Drives starter control relay 0 V for 2 seconds after turning ignition switch ON (II), then battery voltage (intake air and/or fuel temperature below 0 °C)
21 LT GRN/RED TF0 (FUEL TANK TEMPERATURE (FTT) SENSOR) Detects FTT sensor signal With ignition switch ON (II): about 0.1-4.8 V (depending on fuel temperature)
22 WHT/BLK BKSW (BRAKE PEDAL POSITION SWITCH) Detects brake pedal position switch signal With brake pedal released: about 0 V
With brake pedal pressed: battery voltage
23 LT BLU K-LINE Sends and receives HDS or scan tool signal With ignition switch ON (II): pulses or battery voltage
24 YEL SEFMJ Communicates with multiplex control unit With ignition switch ON (II): about 5 V
With engine running under load: pulses
25 BLU/WHT VSSOUT (VEHICLE SPEED SIGNAL OUTPUT) Sends vehicle speed signal With ignition switch ON (II) and front wheels rotating: cycles about 0 V to 5 V or battery voltage
26 BLU NEP (ENGINE SPEED PULSE) Outputs engine speed pulse With engine running: pulses
27 RED/BLU IMOCD (IMMOBILIZER CODE) Detects immobilizer signal  
28 PUR P1SW (FUEL PRESSURE REGULATOR SWITCH) Detects fuel pressure regulator switch signal With ignition switch ON (II): about 0 V
29 BRN SCS (SERVICE CHECK SIGNAL) Detects service check signal With the service check signal shorted with the PGM
Tester: about 0 V
With the service check signal opened: about 5 V
30 RED/WHT WEN (WRITE ENABLE SIGNAL) Detects write enable signal With ignition switch ON (II): about 0 V
31 GRN/ORN MIL (MALFUNCTION INDICATOR LAMP) Drives MIL With MIL turned ON: about 0 V
With MIL turned OFF: battery voltage