Engine Controls - Self-Diagnostics - Testing - I30: Other Infiniti I30 I

ELECTRONIC CONCENTRATED CONTROL SYSTEM (ECCS)

Self-diagnostic system is used for diagnosing malfunctions of Electronic Concentrated Control System (ECCS) sensors and actuators. Electronic Control Module (ECM) has 2 available diagnostic modes. Before entering self-diagnostics, perform BASIC DIAGNOSTIC PROCEDURES. This prevents wasted diagnostic time and invalid diagnostic results.

Scan Tester

In addition to self-diagnostic capability, all models are equipped with a Data Link Connector (DLC) for use with OBD-II compatible Generic Scan Tester (GST). DLC is located under left side dash side panel near brake pedal. (Scheme 4)

Note. When performing BASIC DIAGNOSTIC PROCEDURES, DO NOT erase any diagnostic information stored in ECM memory.

Note. CHECK ENGINE light is now referred to as Malfunction Indicator Light (MIL).

Scheme 4

Hard Failures

Hard failures cause Malfunction Indicator Light (MIL) to glow and remain on until problem is repaired. If light comes on and remains on (light may flash) during vehicle operation, cause of malfunction must be determined using diagnostic trouble code tables. 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, vehicle runs but driveability will not be optimum.

Intermittent Failures

Intermittent failures may cause Malfunction Indicator Light (MIL) to flicker or glow and go out after an intermittent DTC goes away. However, corresponding trouble code will be stored in ECM memory. Not all trouble codes will illuminate MIL. If related DTC does not reoccur within a certain time frame, related trouble code will be erased from ECM memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article.

Note. Follow proper diagnostic routine when diagnosing system. See DIAGNOSTIC ROUTINE table.

DIAGNOSTIC ROUTINE

MALFUNCTION INDICATOR LIGHT (MIL)

Note. Not all trouble codes activate MIL.

All models are equipped with a Malfunction Indicator Light (MIL). As a bulb check, light glows when ignition is turned on and engine is not running.

MIL glows when a DTC is detected with engine running. A corresponding trouble code will set in ECM memory. MIL also glows if ECM or camshaft/crankshaft position sensor malfunctions.

Mode 1: Current Data

This mode accesses current emission related data input and output values. In this mode, system status information is also monitored. If engine is started, MIL and Red LED in ECM should turn off, unless a DTC or trouble code is present.

Mode 2: Freeze Data

This mode accesses information stored during engine operation and may or may not store a trouble code. In this mode, MIL should be off, unless a DTC is present.

Mode 4: Clearing Codes

This mode can clear all emission related diagnostic information and reset status of system.

Mode 5: Heated O2 System Status

This mode accesses ECM monitoring of heated O2 system.

Using MIL

1. Turn ignition on, but leave engine off. Using a small screwdriver, turn diagnostic mode selector on ECM fully clockwise. Wait at least 2 seconds, and then turn diagnostic mode selector fully counterclockwise. Mode II self-diagnostics will result, and MIL and Red LED inspection light will flash codes (if present).
2. If engine is started at this stage, MIL and Red LED inspection light will display condition of air/fuel mixture, monitored by HO2S sensor, whether system is in closed or open loop.

Note. Turn diagnostic mode selector fully counterclockwise whenever vehicle is in use. Switching modes is not possible when engine is running.

Using Scan Tester

Turn ignition off. Connect scan tester to DLC. (Scheme 4) Turn ignition on. Enter program desired to scan tester screen. Perform each diagnostic mode according appropriate service procedure.

Use Mode II to retrieve trouble codes. Read codes using either Malfunction Indicator Light (MIL) or Red LED inspection light on ECM. Trouble codes will flash after selecting Mode II.

Trouble codes are indicated by number of flashes from MIL or Red LED inspection light. For example, 3 long (.6 second) flashes followed by 3 short (.3 second) flashes of MIL or Red LED indicate a Code 303. There will be a .9 second pause between long and short flash groups. There will be a 2.1 second pause between codes.

Turn ignition off. Connect scan tester to DLC. (Scheme 4) Turn ignition on. Follow procedures listed on scan tester menu. See scan tester manufacturer information for additional service procedure.

CLEARING CODES

Note. Ensure all diagnostic codes are accessed from ECM memory before disconnecting battery or switching from Mode II to Mode I.

Stored memory can be erased by disconnecting battery or selecting Mode I after Mode II has been accessed.

Turn ignition off. Connect scan tester to DLC. (Scheme 4) Turn ignition on. Enter CLEAR CODES selection on scan tester menu.

FINAL CHECK FOR ALL CODE CHARTS

Unless otherwise instructed, perform following FINAL CHECK after each repair is completed.

1. Clear all DTCs stored in ECM memory. See «CLEARING CODES»(ref-18020-S33995970462000122900000) under SELF-DIAGNOSTIC SYSTEM.
2. Ensure pass code is displayed on scan tester.
3. Perform a test drive.
4. Verify no DTCs are present in ECM memory. If results are okay, inspection is complete. If results are not okay, repeat circuit test and/or verify ECM pin terminals or harness connector are not damaged.

DTCS P0300-P0306: CYLINDER OR MULTIPLE CYLINDER MISFIRE

If misfire occurs, engine speed will fluctuate and appropriate DTC will set in ECM as follows

1. DTC P0300; multiple cylinder misfire.
2. DTC P0301; cylinder No. 1.
3. DTC P0302; cylinder No. 2.
4. DTC P0303; cylinder No. 3.
5. DTC P0304; cylinder No. 4.
6. DTC P0305; cylinder No. 5.
7. DTC P0306; cylinder No. 6.

1. Basic Inspection - Start engine and run at idle. Listen for intake air leaks. If a leak is detected, repair as required. Stop engine and visually inspect exhaust system, three way catalyst and muffler for damage. Repair as required. If no problems are detected, go to next step.
2. Check EGR Function - See DTC P0400: EGR FUNCTION. Repair as required. If no faults are detected, perform power balance test. Start engine and allow to idle. Individually, disconnect fuel injector harness connectors. If engine speed momentarily drops, go to step 4). If engine speed does not momentarily drop, check appropriate fuel injector. Does injector make operating sound at idle. If no sound is detected, check injector harness for open or short conditions, check injector for proper operation. If no faults are detected, go to next step.
3. Check Ignition System - Disconnect ignition wire from spark plug. Connect a known good spark plug. Place end of spark plug against a suitable ground and crank engine. If no spark is detected, check ignition wires for defects and repair as required. Check ignition coil, power transistor and related circuits. See DTC P1320: IGNITION SIGNAL. If spark is detected, go to next step.
4. Remove spark plugs. Inspect for proper gap, fouling or damage. Replace spark plugs as required. Check fuel pressure. If pressure is not within specifications, check fuel pump and related circuits. Check cylinder compression. If not within specifications, check pistons, rings, valves. Check ignition timing and adjust as required. Check MAF sensor. See DTC P0100: MASS AIRFLOW (MAF) SENSOR.
5. Component Inspection - Inspect ignition wires for cracks, damage, burned terminals and improper fit. Check distributor cap for cracks or dirty and corroded terminals. Disconnect and reconnect harness connectors in circuit and perform FINAL CHECK in Self Diagnostic section.

Check Component

Ensure vacuum system hoses are routed correctly. (Scheme 5) Inspect EGRC-BPT valve and EGR system. See SYSTEM/COMPONENT TESTS article. Repair or replace as required and perform FINAL CHECK in Self Diagnostic section.

Scheme 5

Check Input Signal Circuit

Turn ignition off. Disconnect ECM and A/T control unit harness connectors. Using an ohmmeter, check continuity between ECM harness connector terminal No. 6 and A/T control unit harness connector terminal No. 45 (Red wire). If no continuity exists, repair open in Red wire. If continuity exists, check ECM and A/T control unit harness and connectors for damage or corrosion. Repair or replace as necessary and retest system.

SUMMARY

If no DTCs (or only pass codes) are present, driveability symptoms exist or intermittent codes exist, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.