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.
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HOMESERVICE MANUALSGMC1991JIMMY 5.7 K, AUTOMATIC, 4L60/MD8REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - TESTS W/CODES - GASOLINESELF-DIAGNOSTIC SYSTEMSCAN DATA
1991 GMC Jimmy 5.7 K, Automatic, 4L60/MD8
Scan Data
1991 GMC Jimmy 5.7 K, Automatic, 4L60/MD8SECTION Scan Data
NOTE:
Information contained in the following TABLE is typical of readings taken on vehicle with engine idling, upper radiator hose hot, throttle closed, transmission in Park or Neutral, closed loop status achieved and all accessories off (except as noted in tables). Data parameters are updated every 1 1/2 seconds. Not all devices and systems are used on all models. For additional information, see tester owner's manual.
SCAN TESTER DATA
| Tester Position | Units Measured | Nominal Data Value |
|---|---|---|
| A/C Clutch | On/Off | Off (On With A/C) |
| A/C Request | Yes/No | No/Yes (With Request) |
| Battery Voltage | Volts | 13.5-14.5 |
| Block Learn | Counts | 8-138 (128 Normal) |
| Clear Flood | On/Off | See Tester Manual |
| Coolant Temp | °C | 85-105° (Norm. Temperature) |
| Crank RPM | RPM | 100-900 |
| Cross Counts | Counts | 0-255 |
| Desired RPM | RPM | ECM Desired RPM |
| EGR Duty Cycle | 0-100% | 0/Closed-100/Fully Open |
| IAC | Count | 0-50 |
| Injector Pulse Width | Mil./Sec | .8-3.0 |
| INT (Integrator) | Counts | 110-145 (128 Normal) |
| Knock Retard (ESC) | Counts | 0-255 |
| Knock Signal | Yes/No | Yes When Knock Exists |
| MAT | C | 10-90° |
| MAP | Volts | 1 (idle) To 4.5 (WOT) |
| Open/Closed Loop Status | Ol/Cl | Closed/Open During Extended Idle |
| O2 Sensor | Millivolts | 100 (Lean) To 999 (Rich) |
| 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 (A/T); Spec. +/-50 RPM Neut. (M/T) |
| TCC | On/Off | Off (On With Command) |
| TPS | Volts | 1.25 (Idle) To 5.0 (WOT) |
| Throttle Angle | 0-100% | 0 (Idle) To 100 (WOT) |
| Trouble Codes | Code # | No codes |
| Upshift Light (Man. Trans.) | On/Off | Off |
| VSS Or MPH | MPH | 0-Actual |
| 4th Gear Switch | On/Off | On/4th Gear |
RENDER: 1.0x
NO RELATED
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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.