1993 Mazda MX-3 SELF-DIAGNOSTIC SYSTEM

ARTICLE BEGINNING
1993 ENGINE PERFORMANCE Self-Diagnostics - MX-3 1.6L, Protege & 323 Mazda MX-3 1.6L, Protege & 323

INTRODUCTION
If no faults were found while performing F - BASIC TESTING, proceed with self-diagnostics. If no fault codes or only pass codes are present after entering self-diagnostics, proceed to appropriate H - TEST W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

SELF-DIAGNOSTICSYSTEM

Hard Failures
Hard failures cause malfunction indicator light (CHECK ENGINE) to illuminate and remain on until problem is repaired. Iflight comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic(code) charts. See CODE CHARTS. If a sensor fails, control unit will use a substitute value in its calculations to continue engine operation. In this condition, commonly known as limp-in mode, the vehicle runs but driveability will not be optimum.

Intermittent Failures
Intermittent failures may cause CHECK ENGINE light to flicker or illuminate and go out after the intermittent fault goes away.However, the corresponding trouble code will be retained in ECU memory. If related fault does not reoccur within a certain time frame,related trouble code will be erased from ECU memory. Intermittent failures may be caused by a sensor, connector or wiring related problems. See INTERMITTENTS in H - TESTS W/O CODES article.

RETRIEVING CODES

Accessing Trouble Codes

1. Using jumper wire, connect self-diagnostic connector terminals TEN and GND. See Fig. 1. Connector is located at back ofleft front wheelwell.
2. With ignition on and engine stopped, observe malfunction indicator light (CHECK ENGINE). Note trouble codes. Check TROUBLE CODE IDENTIFICATION chart for possible cause. If light remains on continuously, MIL circuit is grounded or ECU is defective. If no codes are found, go to J - PIN VOLTAGE CHARTS article.

AFTER-REPAIR PROCEDURE

After indicated service or replacement is performed, clear codes. See CLEARING CODES. Recheck PCME memory. No codes should be present. If codes are present, see appropriate trouble code chart under CODE CHARTS to repair vehicle.

CLEARING CODES

Clearing Trouble Codes

• Disconnect negative battery cable. Depress brake pedal for at least 5 seconds. Reconnect battery cable.
• Ground test connector with jumper wire. Turn ignition on, but DO NOT start engine for 6 seconds. Start and run engine at 2000 RPM for 2 minutes. Verify no codes are displayed.

CODE CHARTS
NOTE: See J - PIN VOLTAGE CHARTS article to identify ECU connector terminals.
NOTE: Trouble Codes No. 6, 12, 55, 60, 61, 62 and 63 are automatic transmission related problems. If codes are present, see appropriate TRANSMISSION SERVICE & REPAIR article.

TROUBLE CODE IDENTIFICATION
TEST SW/CODES-4-CYL 1993 Mazda MX-3 For NO