Engine Controls - Pin Voltage Charts: Introduction

Pin voltage charts are supplied to reduce diagnostic time. Checking pin voltages at Electronic Control Unit (ECU) determines whether ECU is receiving and transmitting proper voltage signals. Charts may also help determine if ECU harness is shorted or opened.

Perform all voltage measurements with Sub-Harness (SST 09842-87704-000) installed between ECU and engine wiring. See Fig 1. Battery negative cable must be disconnected when installing and removing sub-harness or engine wiring at ECU. Ensure battery voltage is greater than 11 volts.

Perform all resistance measurements with Sub-Harness (SST 09842-87704-000) connected to engine wiring only.

CAUTION: When performing resistance checks DO NOT connect sub-harness to ECU or touch ECU terminals with an ohmmeter.

Terminal identification on all pin voltage and resistance tables refers to terminal numbers of sub-harness. For correlation to ECU terminals, see appropriate SUB-HARNESS/ECU TERMINAL IDENTIFICATION table. Also see WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section. For sub-harness terminal identification, see Fig 2.

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.

Fig 1: Installing Sub-Harness (SST 09842-87704-000)

Courtesy of DAIHATSU MOTOR CO. LTD.

Fig 2: Identifying Sub-Harness Terminals

Courtesy of DAIHATSU MOTOR CO. LTD.