Table of Contents 623 Electrical Circuit Diagnosis Diagnosis and Testing ...................................................................... 228 Charging System Visual Inspection .................................................. 229 Battery Inspection ......................................................................... 230 Fusing ........................................................................................... 231 Alternator Drive Belt ..................................................................... 232 Alternator Inspection .....................................................................
233 Alternator Output Test (no load) ....................................................... 234 Alternator Output Test (with load) ..................................................... 236 Voltage Drop Tests ........................................................................... 237 Clutch Pulley Lock Function Test ..................................................... 238 Section 9: Introduction to Section 9 Topics ............................................................................... 243 Electronic Signals .............................................................................
244 Electronic Signals Analog Signals .............................................................................. 245 Digital Signals ............................................................................... 246 Electronic Control Units .................................................................... 247 Input Signals ................................................................................. 247 Output Signals .............................................................................. 247 Engine Control Module ................................................................. 248 ECU Data Processing ...................................................................
249 Digital Signals ........................................................................... 249 Analog Signals .......................................................................... 249 Look-up Tables ......................................................................... 249 ECU Output Signals ..................................................................... 250 Oscilloscopes ................................................................................... 251 Oscilloscope Display .................................................................... 252 Battery Voltage .........................................................................
253 TPS Signal ................................................................................ 254 Fuel Injector Signal ................................................................... 255 Troubleshooting with an Oscilloscope .............................................. 256 PicoScope™ ..................................................................................... 257 Connecting the Leads ................................................................... 257 PicoScope Features ..................................................................... 257 Appendix Appendix Topics ............................................................................... 261 A.
Body Electrical Diagnosis Quick Reference ................................. 263 B. Normal Circuit Operation .............................................................. 264 Common Electrical Tests .............................................................. 265 Available Voltage Test ............................................................ 265 Voltage Drop Test ................................................................... 266 Typical Types of Circuit Faults .................................................... 267 Open in Series Part of Circuit ................................................. 267 Open In Parallel Branch .........................................................
268 High Resistance on Power Side of Load ................................ 269 High Resistance on Ground Side of Load .............................. 270 Short to Ground ...................................................................... 271 iv Technical Training