Engine Controls - Tests W/Codes: Introduction

NOTE: The XJS 5.3L V12 does not have a check engine light or diagnostic capabilities.

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES in BASIC TESTING article, proceed with self-diagnostics. If no fault codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article in this section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).