Engine Controls - System & Component Testing: Introduction

Before testing separate components or systems, perform procedures in BASIC DIAGNOSTIC PROCEDURES article. Since many computer-controlled and monitored components set a Diagnostic Trouble Code (DTC) if they malfunction, also perform procedures in appropriate SELF-DIAGNOSTICS article.

WARNING: On MDX models, the PCM overwrites data and monitors the EVAP system for up to 60 minutes after the ignition is turned off. Jumping the SCS line after turning ignition off cancels this function. Disconnecting the PCM during this function, without jumping the SCS line first, can damage the PCM. When removing/installing PCM or disconnecting PCM connectors, steps 1 - 3 must be followed to protect the powertrain control module (PCM) from damage, or wait at least 60 minutes before disconnecting. See the following:

With ignition on, connect the Honda PGM Tester or the HDS to the data link connector (DLC), and go into any of the live data screens.
Turn ignition off.
Turn the Honda PGM Tester off or close the HDS and then back on. Go to the SCS mode and follow the screens to ground the 16-pin DLC.

NOTE: Before disconnecting battery, obtain anti-theft code and presets for radio. After battery is reconnected, CODE will appear on radio display. Enter 5-digit anti-theft code using select buttons and radio will begin working. If code is entered wrong 3 times, leave radio on at least one hour and enter code correctly. Any time radio power is lost, pre-selected radio stations will have to be reset.

NOTE: Testing individual components does not isolate short or open circuits. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.