Engine Controls - Tests W/Codes - 4.2L: Introduction

NOTE: Diagnostic information for 400E is not available. Limited diagnostic information is available for LH-SFI vehicles.

If no faults were found while performing preliminary inspection, go to RETRIEVING CODES in this article. If no fault codes or only pass codes are present, go to the TESTS W/O CODES in the ENGINE PERFORMANCE section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

NOTE: All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated different in testing procedures.