Chapter 25 PowerPoint

Define these Technical Terms using the textbook:

1. intermittent

2. junction block

3. memory saver

4. pin number

5. pin point test

6. preliminary visual inspection

7. relay tester

8. relearn procedure

9. sensor socket

10. stress testing

Answer these discussion questions using the textbook:

1. Name one safe working practice when servicing automotive computers.

Read the chapter summary below:

■ Pinpoint tests are specific tests of individual components. They are completed after scanning for trouble codes.

■ A preliminary inspection involves looking for signs of obvious trouble: loose wires, leaking vacuum hoses, part damage, etc.

■ Semiconductors are very easy to damage. They can be damaged by static electricity, voltage spikes, heat, and impact shocks.

■ Stress testing refers to the use of heat, cold, or moisture to simulate extreme operating conditions of components, like an electronic control unit.

■ Poor electrical connections are the most common cause of electrical-related problems in a computer system.

■ Vacuum leaks are frequently caused by deteriorated, broken, or loose vacuum hoses. Vacuum leaks often make a hissing sound.

■ A reference voltage (typically 5 volts) is fed to switching and variable resistance type sensors.

■ Sensor sockets have a deep pocket and a cut out for a sensor pigtail (wires).

■ Since they contain movable contact points, relays are a common source of computer system problems.

■ Computer service usually involves a few tests and computer replacement if needed.

■ Some computers use the old PROM (memory chip) during computer replacement, since it stores data for the specific make and model vehicle.