Section 3 · Pages 31–148 (118 pages)

Computer Command Control (Using Scan Tool Diagnosis)

From the 1988 GMC Light Duty Truck Fuel, Emissions and Driveability Manual

The heart of the manual: diagnosis of the Computer Command Control system with a Scan tool. It describes the ECM and its inputs, including the coolant temperature, MAP, oxygen, throttle position, vehicle speed and MAT sensors, the park/neutral and power steering pressure switches and A/C signals, then works through the diagnostic charts, such as chart A-3 (engine cranks but will not run) and A-4 (injector circuit diagnosis), and on-vehicle service of the ECM, connectors and wire harness.

Read this section free, starting at page 31

What this section covers

  • ECM and sensor descriptions
  • Throttle position sensor output by TBI unit
  • Diagnostic charts
  • Engine cranks but will not run
  • Injector circuit diagnosis
  • Checking fuel gage (two fuel tanks)
  • On-vehicle service and wire harness
Year
1988
Make
GMC
Vehicle
C/K Trucks, G Vans, Light Duty Trucks, M Vans (Astro/Safari), P Forward Control, R/V Trucks, S/T Trucks, Trucks
Type
Fuel & Emissions, Supplement
Models
R/V, G, P, S/T, M, C/K 10–30
Publication
X-8836
Pages
290

What’s inside

Front matter

  1. Foreword and ContentsForeword listing the engines covered and the service manuals this book supplements, metric fastener cautions, the action symbols used in the procedures, and the table of contents.pp. 3–6

Manual

  1. 1General Informationpp. 7–24
  2. 2Driveability Symptomspp. 25–30
  3. 3Computer Command Control (Using Scan Tool Diagnosis)pp. 31–148
  4. 4Fuel Control Systempp. 149–192
  5. 5Evaporative Emission Control System (EECS)pp. 193–198
  6. 6Ignition System/ESTpp. 199–206
  7. 7Electronic Spark Control (ESC)pp. 207–210
  8. 8Air Management Systempp. 211–220
  9. 9Exhaust Gas Recirculation (EGR) Systempp. 221–230
  10. 10Automatic and Manual Transmission Controlspp. 231–240
  11. 11Positive Crankcase Ventilation (PCV)pp. 241–244
  12. 12Thermostatic Air Cleaner (THERMAC)pp. 245–250
  13. 13Special Toolspp. 251–258
  14. 14Abbreviations and Glossary of Termspp. 259–262
  15. 15Computer Command Control (Without Using Scan Tool Diagnosis)pp. 263–290

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