Engine Controls - Pin Voltage Charts: Introduction

Pin voltage charts are supplied to reduce diagnostic time. Checking pin voltages at the Programmed Fuel Injection Electronic Control Unit (PGM-FI ECU) determines whether it is receiving and transmitting proper voltage signals. Diagnostic charts may also help determine if ECU harness is shorted or open.

NOTE: Unless stated otherwise in testing procedures, perform all voltage tests using a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance. Voltage readings may vary slightly due to battery condition or charging rate.

CONNECTOR "A" TERMINAL PIN VOLTAGE

TERMINAL ID & (WIRE COLOR)

FUNCTION

VOLTAGE VALUE

A1 (Brown)

Injector No. 1

VBAT ⁽¹⁾

A2 (Black)

Power Ground

Less Than 1V

A3 (Red)

Injector No. 2

VBAT ⁽¹⁾

A4 (Black)

Power Ground

Less Than 1V

A5 (Lt Blue)

Injector No. 3

VBAT ⁽¹⁾

A6 (Green)

Purge Cut-Off Solenoid Valve

N/A

A7 (Yellow)

Injector No. 4

VBAT ⁽¹⁾

A8 (Red)

EGR Control Solenoid Valve (A/T)

N/A

A10 (Grn/Yel)

Pressure Regulator Cut-Off Solenoid Valve

N/A

A11 (Blu/Yel)

Electronic Air Control Valve

VBAT ⁽¹⁾

A12 (Grn/Blk)

Fuel Pump Control Circuit

N/A

A13 (Yel/Blk)

Battery Voltage From Main Relay

VBAT ⁽¹⁾

A14 (Grn/Blk)

Fuel Pump Control Circuit

N/A

A15 (Yel/Blk)

Battery Voltage From Main Relay

VBAT ⁽¹⁾

A16 (Brn/Blk)

Ground

Less Than 1V

A17

Not Used

N/A

A18 (Blk/Red)

Ground

Less Than 1V

⁽¹⁾

KOEO - Key on, engine off.

CONNECTOR "B" TERMINAL PIN VOLTAGE

TERMINAL ID & (WIRE COLOR)

FUNCTION

VOLTAGE VALUE

B1 (Wht/Yel)

B + From Battery

Battery Voltage At All Times

B2 (Blue)

Fast Idle Control Solenoid Valve (A/T)

N/A

B3 (Yellow)

A/C Clutch Relay

N/A

B4 (Blu/Wht)

To A/T Control Unit

N/A

Not Used

N/A

B6 (Grn/Orn)

Check Engine Light Circuit

N/A

B7 (Green)

A/T Shift Position Switch (P/N)

⁽¹⁾

B8 (Blu/Red)

A/C Switch Circuit

⁽²⁾

Not Used

N/A

B10 (Orange)

Crank Sensor Circuit

N/A

B11

Not Used

N/A

B12 (White)

Crank Sensor Circuit

N/A

B13 (Blu/Wht)

Start Signal Input

VBAT in START

B14 (Blue)

Alternator Charging Signal

5V ⁽³⁾⁽⁴⁾

B15 (White)

Ignitor Control Circuit

10V ⁽³⁾

B16 (Yel/Red)

Vehicle Speed Sensor

Switches 0-5V ⁽⁵⁾

B17 (White)

Ignitor Control Circuit

10V ⁽³⁾

B18

Not Used

N/A

B19 (Red)

P/S Pressure Switch

⁽⁶⁾

B20 (Brown)

Ignition Timing Adjustment Connector

N/A

⁽¹⁾

Less than one volt in Park or Neutral.

⁽²⁾

5V KOEO & A/C off, less than 1V KOEO & A/C on.

⁽³⁾

Key on, engine off.

⁽⁴⁾

Decreases under electrical load (Headlights, Defogger on) at warm idle.

⁽⁵⁾

While turning left front wheel.

⁽⁶⁾

Less than battery voltage with front wheels straight ahead (key on, engine off), battery voltage while slowly turning steering wheel (key on, engine running).

CONNECTOR "C" TERMINAL PIN VOLTAGE

TERMINAL ID & (WIRE COLOR)

FUNCTION

VOLTAGE VALUE

C1 (Blu/Grn)

CYL Sensor Circuit

N/A

C2 (Blu/Yel)

CYL Sensor Circuit

N/A

C3 (Orn/Blu)

TDC Sensor Circuit

N/A

C4 (Wht/Blu)

TDC Sensor Circuit

N/A

C5 (Red/Yel)

Intake Air Temp Sensor Signal

⁽¹⁾

C6 (Red/Wht)

Coolant Temp Sensor Signal

⁽¹⁾

C7 (Red/Blu)

Throttle Angle Sensor Signal

⁽²⁾

C8 (Grn/Red)

EGR Valve Lift Sensor Signal (A/T)

⁽³⁾

C9 (Red/Wht)

A/T Control Unit Signal Input

N/A

C10 (Grn/Wht)

Brake Switch Signal Input

⁽⁴⁾

C11 (White)

MAP Sensor Signal

0.3-4.5V ⁽⁵⁾

C12 (Grn/Wht)

Sensor Ground (Except MAP Sensor) Released.

N/A

C13 (Yel/Wht)

Sensor Power (Except MAP Sensor)

5V ⁽⁶⁾

C14 (Grn/Wht)

MAP Sensor Ground

N/A

C15 (Yel/Red)

MAP Sensor Power

5V ⁽⁶⁾

C16 (White)

O2 Sensor Signal

⁽⁷⁾

⁽¹⁾

0.5-4.5V (Varies with temperature).

⁽²⁾

0.5V KOEO at closed throttle, about 4.5V at WOT.

⁽³⁾

1.2V at warm idle.

⁽⁴⁾

VBAT with KOEO with brake applied.

⁽⁵⁾

Varies with manifold pressure.

⁽⁶⁾

Key on, engine off.

⁽⁷⁾

+0.6V warm engine @ 4500 RPM, 0.4V throttle quickly released.

Fig 1: Identifying Connector "A" Terminals

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 2: Identifying Connector "B" Terminals

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 3: Identifying Connector "C" Terminals

Courtesy of AMERICAN HONDA MOTOR CO., INC.