Scan Tool Data List
If after completing the on-board diagnostic system check and finding the on-board diagnostics functioning properly and no diagnostic trouble codes displayed "Typical Scan Values" for the appropriate engine may be used for comparison. The "Typical Values" are an average of display values recorded from normally operating vehicles and are intended to represent what a normally functioning system would display.
CAUTI0N: If a scan tool displays any data known to be inaccurate or faulty, the tool should not be used for diagnosis. Using a faulty or incompatible scan tool can result in misdiagnosis and unnecessary parts replacement.
Only the parameters listed below are used in this manual for diagnosis. If a scan tool reads other parameters, the values are not recommended by General Motors for use in diagnosis.
NOTE: If all values are within the range illustrated, refer to Diagnosis By Symptom. Testing and Inspection
NOTE: Be sure the following conditions are met when recording actual data values.
^ Engine at normal operating temperature (upper radiator hose hot)
^ Engine idling at closed throttle
^ Transmission gear selector in "Park" or "Neutral" position
^ System operating in "Closed Loop"
^ All Accessories and A/C turned OFF
^ Brake Not Applied
TYPICAL SCAN DATA VALUES
TECH-1 PARAMETER UNITS TYPICAL DATA VALUE
Engine Speed RPM 650-75
Desired Idle RPM 675
Eng Cool Temp °C °F Varies (85°-105°C) (185°-220°F)
Intake Air Temp °C °F Varies with air temp.
Throttle Position Volts .20-.74
Throttle Angle Percent G0%
Mass Air Flow Gm/Sec 4.9 (varies)
Calc Eng Load Counts 70-80
HO2S 1 mV Varies (100-1000)
HO2S 2 mV Varies (100-1000)
HO2S 1 Cross Cnts Counts Varies
Rich/Lean Status Rich/Lean Rich/Lean Changing Constantly
Mph / Km/h Mph, Km/h 0, 0
Spark Advance Degrees 1 6°(Varies)
Inj Pulse Width Gmsec Varies
S.T. Fuel Trim Counts 95-140*
L.T. Fuel Trim Counts 95-138*
Loop Status Open Lp/Closed Lp Closed Lp
Fuel Trim Cell Cell#
Knock Retard Degrees 0°
Knock Signal Yes/No No
Idle Air Control Counts 16-20
Park/Neutral Pos P-N/R-DL P-N
TCC Brake Switch Applied/Released Released
TCC Mode On/Apply/Off/Release Off
TCC Duty Cycle Percent 0%
TCC Slip RPM +254
N/V Ratio Counts 0
Current Weak Cyl Cylinder #/None None
EGR Pintle Pos Volts 0-1
Cam/Crank Error Counts 0-2 (Varies)
A poor PCM ground at the ignition control module mounting bracket to engine could cause short term fuel trim and long term fuel trim to read above 150; make a careful physical inspection of this critical connection.
Trans Fluid Temp °C°F Varies
Fuel EVAP Purge Percent Varies
System Voltage Voltage 13.5 (varies)
A/C Request Yes/No No
A/C Clutch On/Off Off
Fan 1 Fan 2 On/Off Off
A/C Head Press. Ok/High OK
EGR Actual Pos Percent 0%
EGR Desired Pos Percent 0%
SMCC Inhibited Yes/No Yes
SMCC Status Engage/Disengage Disengage
Shift Solenoid A On/Off On
Shift Solenoid B 8On/Off On
PRNDL P High/Low Low
PRNDL A High/Low Low
PRNDL B High/Low High
PRNDL C High/Low High
Trans Range Switch Low/Drive 2/Drive 3/Drive 4/
Neutral/Reverse/Park Park
Commanded Gear First/Second/Third/Fourth 1st
P/N Yes/No Yes
2nd Actual Yes/No No
3rd Actual Yes/No No
4th Actual Yes/No No
QDM 1 High/Low Low
QDM 2 High/Low Low
QDM 4 High/Low Low
PASS-KEY II Fuel Enabled/Disabled Enabled
Calibration ID Prom ID # Internal l.D. only
Time From Start Minutes Varies
NOTICE: IF all values are within the range illustrated, refer to Diagnosis by Symptom.Testing and Inspection