Engine: Service Precautions

Precautions for Engine

Reassembling Note for Wiring Harness
Be sure to observe Reassembling Note for Wiring Harness whenever installing wiring harness. Otherwise, electrical trouble may occur.

Precautions for Engine Service

CAUTION:
The following information on engine service should be noted carefully, as it is important in preventing damage and in contributing to reliable engine performance.

^ When raising or supporting engine for any reason, do not apply a jack under oil pan. Due to small clearance between oil pan and oil pump strainer, jacking against oil pan may bend it against strainer, resulting in damaged oil pick-up unit.
^ It should be kept in mind, while working on engine, that 12-volt electrical system is capable of violent and damaging short circuits. When performing any work where electrical terminals could possibly be grounded, ground cable of battery should be disconnected at battery.
^ Any time the air cleaner, throttle body or intake manifold is removed, the intake opening should be covered. This prevents accidental entry of foreign material into cylinder which will cause extensive damage when engine is started.

Precautions for Diagnosing Trouble
^ Do not disconnect ECM connectors from ECM, battery cable from battery, ECM ground wire harness from engine, "B/U" fuse or "DOME" fuse before confirming diagnostic information (pending DTC, confirmed DTC, freeze frame data, etc.) other than permanent DTC stored in ECM memory. Such disconnection will erase memorized information in ECM memory.
^ Before using scan tool, read its "Operator's (Instruction) Manual" to know how to use it.
^ Priorities for diagnosing troubles
If two or more diagnostic trouble codes (DTCs) are stored, proceed to the flow of the DTC which has detected earliest in the order and follow the instruction in that table. If no instructions are given, troubleshoot DTCs according to the following priorities.
a. DTCs other than DTC P0171 / P0172 (Fuel system too lean / too rich) and DTC P0300 / P0301 / P0302 / P0303 / P0304 (Misfire detected)
b. DTC P0171 / P0172 (Fuel system too lean/too rich)
c. DTC P0300 / P0301 / P0302 / P0303 / P0304 (Misfire detected)
^ Upon completion of inspection and repair work, perform "DTC Confirmation Procedure" and confirm that the trouble has been repaired.
^ Be sure to clear all DTCs after completing troubleshooting.

Precautions for Replacing ECM
^ ECM must be replace with new one.
^ Perform Procedure after ECM Replacement.

Precautions for ECM Circuit Inspection
When measuring circuit voltage and/or pulse signal at ECM connector, connect special tool to ECM and ECM connectors referring to Inspection of ECM and Its Circuits and noting the following points.
^ ECM connectors are waterproofed. Each terminal of ECM connectors is sealed with grommet. Therefore, do not insert the tester probe into sealed terminal from harness side. When measuring circuit voltage and/or pulse signal at ECM connector, be sure to connect special tool to ECM connectors and insert tester probe into special tool's connectors at harness side. Otherwise, ECM and its circuits may be damaged by water.
^ Wire colors of special tool connectors are different from wire colors of ECM connectors. However, terminal arrangement of special tool connectors are the same as terminal arrangement of ECM connectors. Therefore, be sure to identify terminal location to measure proper terminal.