Vehicle Damage Warnings
ELECTRICAL AND ELECTRONIC COMPONENTS1. Always ensure the battery is properly connected to the vehicle prior to attempting to start engine.
2. Don't disconnect the battery when the engine is running.
3. Fully release locks prior to disconnecting connections, ensure connectors are fully seated and all insulators and shields are in place when reinstalling.
4. Never connect or disconnect electrical connections with the ignition switch in the "ON" position unless specifically directed to do so in a test procedure.
5. In order to disable the ignition system, unplug the primary connections only. NEVER disconnect the secondary leads to disable the ignition system.
6. Do not use a self powered test lamp to check continuity.
7. Do not create any arcing to check the continuity of a circuit.[a]
8. When charging the battery, ensure battery cables are removed.
9. When replacing electronic components, disconnect the battery ground.
10. Perform an ECM Circuit Resistance Check before replacing a faulty ECM.[b]
NOTE: Before removing battery ground, record stored trouble codes. ECM memory will be erased when ground cable is removed.
11. When measuring voltage at the control unit harness connector, disconnect harness connector first, then turn ignition "ON" as necessary.
12. To prevent deforming of the electronic control unit harness connectors, do not probe terminals directly. Instead, insert a pin from the harness side and perform measurements through pin.
13. Avoid getting water on any of the Fuel or Engine Control System Components.
14. Fuel and Engine Control System wiring should be at least 4 inches away from high tension cables.
15. Never pierce ignition leads or insulator boots to connect timing lights or analyzers. Use proper adapters.
16. When removing a spark plug wire, twist the boot one quarter turn and pull on the boot only, never the lead itself.
17. Always use recommended power source in each testing procedure.
18. Never apply battery power to a component unless told to do so in a test procedure.
19. Do not try to disassemble the control unit.
20. Never use an auxiliary starting assist device which has a voltage rating above 12 volts to start engine.
21. In cases of electrical welding (for instance, spot welding), disconnect the climate control, injection, cruise control, ECU and radio.
22. In case of temperature above 176°F (80°C), (example: infra-red spray booth), remove all ECMs.
23. The battery produces an explosive gas (hydrogen), avoid creating sparks near battery.
[a] ELECTRICAL CHARGE AND DISCHARGE
Electronic components used in automotive computers are designed to operate at very low voltages (3-5 Volts), and are extremely susceptible to damage caused by static electrical discharge. Voltages as low as 12 volts can damage computer circuits. By comparison, it takes as much as 4,000 volts of static discharge for a person to feel the "ZAP", and there is no way of knowing whether the charge is positive or negative in polarity. There are several ways in which a person can become statically charged. The most common methods of charging are by friction or induction. Friction between organic materials (such as cotton or leather) and synthetics (such as plastic, vinyl, or glass) will generate static charges as great as 25,000 volts. This can happen by simply sliding across a car seat or by wearing a cotton shirt under a coat made of synthetic materials. Charging by induction occurs when a person standing near a highly charged object (strong magnetic field such as a transformer) momentarily touches ground. Like charges are displaced to ground, leaving the person highly charged with the opposite polarity. Static charges are gradually equalized by moisture in the air, but are retained much longer when the humidity is low. Use care when handling and testing electronic components.
[b] PROPER TOOLS AND TESTING PROCEDURES
Use a digital multi-meter with a minimum of 10 mega-ohms internal impedance when testing the control unit or related components, unless the use of an analog meter is specified by the testing procedure. Do NOT use a self-powered test lamp to check for continuity. Analog meters have a low internal impedance and cause circuit "loading" in low voltage circuits, resulting in inaccurate measurements and possible damage to components. Use of a multi-meter is necessary to obtain accurate measurements and to avoid damaging low voltage control unit circuits and components.
FUEL SYSTEMS
1. Do not operate the fuel pump without fuel in the lines.
2. On fuel injected models do not depress the accelerator pedal while trying to start the car.
3. Handle all fuel injection related parts with care as they may easily become damaged.
4. Always use new gaskets or O-rings when installing fuel lines or injectors.
5. Lightly lubricate O-rings and flare connections with gasoline. Do not use gear lubricant or brake fluid.
6. Relieve the fuel system pressure before servicing the components.
7. When servicing fuel system components, unless otherwise specified, disconnect the negative battery cable to avoid the discharge of fuel if an accidental attempt is made to start the car.
8. Loosen the fuel tank filler cap to relieve the fuel tank vapor pressure.
9. Never drain or store fuel in an open container due to the possibility of fire or explosion.
10. Always have a "Class B" fire extinguisher near the work area.
11. Due to the high pressures involved, Do Not attempt to repair flexible fuel supply lines due to possible safety hazards. Replace only with the same type of flexible fuel lines and fittings as those removed.
12. Do Not use copper or aluminum tubing to replace steel tubing. Those materials do not have the satisfactory durability to withstand normal vehicle vibrations.