Vehicle Damage Warnings
ELECTRICAL AND ELECTRONIC SERVICEELECTROSTATIC DISCHARGE DAMAGE
Electronic components used in automotive computer systems are designed to operate at very low voltages (3-5V) and are extremely susceptible to damage caused by static electrical discharge. As little as 12V can damage computer circuits. By comparison, it takes as much as 4,000V of static discharge for a person to even feel the "ZAP."
There are several ways a person may become statically charged, the most common of which are friction and induction. Friction between organic materials (such as cotton and leather) and synthetics (such as plastic, vinyl and glass) can generate static charges as great as 25,000V. This can occur by simply sliding across a car seat or by wearing a cotton shirt under a coat of synthetic fabric. Charging by induction occurs when a person standing near a highly charged object (such as a transformer) momentarily touches ground. Like charges are displaced to ground, leaving the person highly charged with opposite polarity. Static charges are gradually equalized by moisture in the air but are retained much longer when humidity is low. Carefully consider electrostatic discharge damage when handling and testing electronic components.
USE OF PROPER TOOLS AND TESTING PROCEDURES
Use a digital volt/ohm meter (DVOM) with a minimum 10 megohms internal impedance when testing computerized engine control components unless use of an analog meter is specified by a testing procedure. A DVOM is necessary to obtain accurate measurements and avoid damaging low voltage circuits and components.
Analog meters have low internal impedance and cause circuit "loading" in low voltage circuits. This will result in inaccurate measurements and may damage components.
Always follow recommended testing procedures. Never ground or apply voltage to a circuit unless specified by a testing procedure. ECM's provide a regulated constant low voltage source to some circuits which may require a minimum resistance (impedance) to operate. Directly grounding or applying battery voltage to these circuits could damage the ECM and cause failure of the related system.
PRECAUTIONS FOR TESTING AND HANDLING ELECTRONIC COMPONENTS
1. Discharge static charges before handling sensitive parts by touching ground. It is good practice to maintain a ground connection to a bare skin area like the wrist when servicing sensitive parts.
2. Never touch ECM connector pins, integrated circuit connector pins or soldered components on the ECM circuit board.
3. Always ensure that the battery is properly connected before attempting to start the engine.
4. Do not disconnect the battery when the engine is running.
5. Fully release connector locks when disconnecting. Ensure connectors are fully seated with insulators and shields in place when reinstalling.
6. Never connect or disconnect electrical connections with ignition "ON" unless specifically directed to do so in a test procedure.
7. NEVER disconnect secondary leads to disable the ignition system. Unplug the primary connections only.
8. Do not use a self powered test lamp to check continuity.
9. Do not create any arcing to check circuit continuity.
10. Disconnect vehicle battery cables when charging the battery.
11. Disconnect the battery ground when replacing electronic components.
NOTE: Access trouble codes before disconnecting battery. Interrupting power supply will erase computer memory.
12. When measuring voltage at the control unit harness connector, first disconnect the harness connector and then turn ignition "ON" as necessary.
13. To prevent deforming control unit harness connectors, do not probe terminals directly. Insert a pin from the harness side and perform measurements through pin.
14. Avoid getting water on any electronic components.
15. Maintain a clearance of at least 4 inches between electronic systems wiring and high tension cables.
16. Never pierce ignition leads or insulator boots to connect timing lights or analyzers. Use proper adapters.
17. When removing spark plug wires, twist and pull on the boot and never the lead itself.
18. Always use 12V batteries as a power source.
19. Never apply battery power to a component unless directed to do so in a test procedure.
20. Do not attempt to disassemble the control unit.
21. Never use a booster/starter rated over 12V to start the engine.
22. Before performing electric arc welding, disconnect climate control system, injection system, cruise control system, ECM and any electronic entertainment devices.
23. Remove all ECM's whenever temperatures may exceed 80~C (176~F). For example, this condition may occur in an infra-red spray booth.
24. Avoid creating sparks near the battery; it contains acid and emits explosive hydrogen gas.
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 be 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 engine oil, gear lubricant or brake fluid.
6. After servicing fuel system, check for leaks and correct as needed.
ENGINE AND EXHAUST
1. On vehicles equipped with catalytic converters, the following conditions must be observed:
a. Use only "UNLEADED FUEL".
b. Avoid running out of fuel.
c. In case of poor engine operation (misfiring), avoid driving the vehicle and correct the problem as soon as possible.
d. Do not disconnect a spark plug wire with the engine running.
e. Avoid push starting the vehicle.
f. If running on a dynamometer, make sure the catalytic converter is well ventilated.
g. Use caution when working near the catalytic converter to prevent the possibility of burns.
2. Do not use silicone based products on an oxygen sensor equipped vehicle to avoid damaging the sensor.
3. When performing a compression test, remove the fuel pump relay. (This will prevent fuel flow to the injectors and resultant engine flooding).