Self-Diagnostic System: Introduction

WARNING: This page is about a different car, the 1989 Nissan 240SX. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: It is important when diagnosing Nissan's ECCS that the proper diagnostic routine be followed. See DIAGNOSTIC ROUTINE table for correct order of procedure.

DIAGNOSTIC ROUTINE

Procedure

Order

Basic Diagnostic Procedures

1st

Entering Diagnostics

2nd

Retrieving Trouble Codes

3rd

Symptoms ⁽¹⁾

4th

Intermittents ⁽¹⁾

5th

⁽¹⁾	Symptoms and intermittents are covered in TESTS W/O CODES article.

NOTE: For additional information on self-diagnostic system, see THEORY/OPERATION article.

If no faults were found while performing BASIC TESTING , proceed with ENTERING SELF-DIAGNOSTICS in this article. If no fault codes or only pass codes are present, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e. ROUGH IDLE, NO START, etc.).

The self-diagnostic system is used for diagnosing malfunctions of major sensors and actuators of the Electronic Concentrated Control System (ECCS). The Electronic Control Unit (ECU) has 5 available diagnostic modes within the computer. Before selecting any mode of self-diagnosis, always perform F - 4-CYL BASIC TESTING first. This will eliminate wasted diagnostic time and invalid diagnostic results.

NOTE: When performing F - 4-CYL BASIC TESTING, be careful not to erase any diagnostic information stored in the ECU memory.