Honda Prelude Si 1992 - 1992 ENGINE PERFORMANCE Self-Diagnostics

Honda Prelude Si 1992 - INTRODUCTION

If no faults were found while performing BASIC TESTING article in the ENGINE PERFORMANCE Section, proceed with self-diagnostics. If no trouble codes or only pass codes are present after entering self-diagnostics, proceed to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.).

Honda Prelude Si 1992 - SELF-DIAGNOSTIC SYSTEM HARD FAILURES

Hard failures cause CHECK ENGINE light to illuminate 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 TROUBLE CODE IDENTIFICATION CHART . 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.

Honda Prelude Si 1992 - 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 50 starter operations, related trouble code will be erased from control unit memory. Intermittent failures may be caused by sensor, connector or wiring related problems. See INTERMITTENTS in TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Honda Prelude Si 1992 - CHECK ENGINE LIGHT

All models are equipped with a CHECK ENGINE light. As a bulb check, light illuminates when ignition is on and engine is not running. CHECK ENGINE light also illuminates when a system failure has been detected and a corresponding trouble code has been set in ECU memory. Not all trouble codes will activate CHECK ENGINE light. If CHECK ENGINE light is on and no codes are in memory, see TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Honda Prelude Si 1992 - RETRIEVING CODES

With ignition off, insert jumper wire in service check connector terminal, located near center console on. See Fig. 1 . Turn ignition on and count flashes on CHECK ENGINE light.

See TROUBLE CODE IDENTIFICATION CHART table and proceed to appropriate TROUBLE CODE CHART for testing. All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless specifically stated differently in testing procedures.

Fig. 1: Honda Prelude Si 1992 - Component Locations - Locating Service Check Connectors

Honda Prelude Si 1992 - TROUBLE CODE DEFINITION

Honda Prelude Si 1992 TROUBLE CODE IDENTIFICATION CHART

Code ⁽¹⁾

System Affected

Probable Cause

ECU

No Signal To ECU

O2 Sensor

Problem In O2 Sensor Circuit

MAP Sensor

Electrical Problem In MAP Sensor

Crank Angle Sensor (CRANK)

Open Or Shorted Signal Circuit

MAP Sensor

Mechanical Problem In MAP Sensor

Coolant Temp. (TW) Sensor

Open Or Shorted Signal Circuit

Throttle Angle Sensor

Open Or Shorted Signal Circuit

Crank Angle Sensor (TDC)

Open Or Shorted Signal Circuit

Crank Angle Sensor (CYL)

Open Or Shorted Signal Circuit

Intake Air Temperature

Problem With Sensor

EGR System

No EGR action

Atmospheric Pressure (PA)

Problem with PA Circuit

Electronic Air Control Valve (EACV)

Open Or Shorted Signal Circuit

Ignition Output Signal

Electrical Problem In Signal Circuit

Fuel Injector

Problem In Fuel Injector Circuit

Vehicle Speed Sensor (VSS)

Open Or Shorted Signal Circuit

Electrical Load Detector

Problem With Electrical Load Detector Circuit

Knock Sensor

Problem With Knock Sensor Circuit

A/T FI Signal A

Problem In A/T Control Unit And ECU Circuit

A/T FI Signal B

Problem In A/T Control Unit And ECU Circuit

O2 Sensor Heater

Problem With O2 Sensor Circuit

Fuel Supply System

Problem With O2 Sensor Circuit Or Fuel System

⁽¹⁾

If codes other than these are indicated, repeat self-diagnosis. If code(s) reappear, substitute a known good ECU, and recheck codes. If code(s) clear, replace ECU.

Honda Prelude Si 1992 - ECU RESET PROCEDURE/CLEARING CODES

To reset ECU, remove BACK UP fuse (CLOCK/RADIO fuse on Prelude) from underhood fuse/relay block. Leave fuse out for 10 seconds to reset ECU. This procedure cancels clock and radio settings, make note of settings before beginning reset procedure.

NOTE:

Some models have an anti-theft code built into the radio circuit. After ECU reset, the radio will not function until code is entered.

Honda Prelude Si 1992 - ECU LOCATION

ECU is located under carpet in passenger-side footwell. See Fig. 1 .

Honda Prelude Si 1992 - SUMMARY

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

Honda Prelude Si 1992 - TROUBLE CODE CHARTS

NOTE:

In the following trouble code charts, illustrations and schematics are courtesy of American Honda Motor Co., Inc.

Honda Prelude Si 1992 - USING TROUBLE CODE CHARTS

To use TROUBLE CODE CHARTS, see RETRIEVING CODES under SELF-DIAGNOSTIC SYSTEM. After codes have been recorded, proceed to appropriate TROUBLE CODE CHART.

When directed by chart to install ECU test harness, turn ignition off. Connect ECU Test Harness (07LAJ-PT3010A ) between ECU and connector. See Fig. 2 . Follow code chart directions.

If CHECK ENGINE light fails to light when ignition switch is turned on, proceed to NO CODE, NO CHECK ENGINE LIGHT chart for appropriate vehicle.

If check engine light stays on for more than 2 seconds after ignition switch is turned on, proceed to CODE/NO CODE, CHECK ENGINE LIGHT STAYS ON chart for appropriate vehicle.