Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1986 Chevrolet Caprice Brougham, 4.3 Z, 700R4/MD8FACTORY OEM SERVICE PROCEDURE
Scan Tester - Test Data Parameters
NOTE:
Information in the following table is a typical reading taken on vehicle with engine idling, upper radiator hose hot, closed throttle, transmission in Park or Neutral, "closed loop" status achieved and all accessories off (except as noted in tables). Data parameters are updated every 1 1/4 seconds. On systems using P-4 computers, parameter updates are virtually instantaneous. Not all devices & systems are used on all models.
FULL FUNCTION (CARBURETED)
| Tester Position | Units Measured | Nominal Data Value |
|---|---|---|
| A/C Clutch | On/Off | Off (On with A/C) |
| A/C Low Freon Switch | On/Off | On when freon low |
| A/C Request | Yes/No | No/Yes(with request) |
| AIR Divert Solenoid | On/Off | On (air to switching sol.) |
| AIR Divert Solenoid | On/Off | Off (air to atmosphere) |
| AIR Switching Solenoid | On/Off | On (to exhaust manifold) |
| AIR Switching Solenoid | On/Off | Off (to catalytic converter) |
| BARO | Volts | 3-4.5 |
| Battery Voltage | Volts | 13.5-14.5 |
| Canister Purge Sol. | On/Off | On cold engine (idle some) |
| Coolant Fan | On/Off | Off below 216°F (102° C) |
| Coolant Temp | °C | 85-105° (norm. temp.) |
| Cross Counts | Counts | 0-255 |
| EFE Sol./Relay | On/Off | On below 85°C |
| EGR Solenoid | On/Off | On when energized |
| EGR Duty Cycle | 0-100% | 0/closed-100/fully open |
| Ignition/Crank | On/Off | On with ignition/crank |
| ILC Solenoid | On/Off | On extended/Off retracted |
| ISC Motor | On/Off | On controls idle |
| ISC Motor | On/Off | Off = no control |
| Knock Retard (ESC) | Counts | 0-255 |
| Knock Signal | Yes/No | Yes when knock exists |
| MAP | Volts | 1 (idle) to 4.5 (WOT) |
| M/C Dwell | Degrees | 10-50° varying |
| Nose Switch | On/Off | On when depressed |
| O2 Sensor | Millivolts | 100 (lean) to 999 (rich) |
| Open/Closed Loop Status | Ol/Cl | Closed/Open during extended idle |
| P/N Switch | P/N/RDL | Park/Neutral |
| P/S Switch | Norm/Hi | Normal |
| PROM I.D. | PROM # | Original factory number |
| RPM | RPM | Spec. +/- 25 RPM Drive (auto.) |
| RPM | RPM | Spec. +/- 50 RPM Neut. (man.) |
| Spark Advance | # of Deg | Varies |
| TCC | On/Off | Off (On with command) |
| Throttle Angle | 0-100% | 0 |
| Throttle Kicker | On/Off | On with A/C & deceleration |
| TPS | Volts | .5 (closed) to 5.0 (WOT.) |
| Trouble Codes | Code # | No Codes |
| Turbo Boost | On/Off | On when activated |
| VAC | Volts | 4.5 (idle) to 1 (WOT) |
| VSS or MPH | MPH | 0-actual |
| WOT Switch | On/Off | On at WOT |
| 3rd Gear Switch | On/Off | On/3rd & 4th gear |
| 4th Gear Switch | On/Off | On/4th gear |
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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