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 +/- 100 RPM from desired RPM (+/- 50 in drive)
Desired Idle RPM PCM idle command (varies with calibration, temp)
Eng. Coolant Temp. °C/°F 85-115C
Intake Air Temp. °C/°F 10°-80°C (depends on underhood temp.)
MAP kPa/Volts 1-3 volts (depends on vacuum & baro pressure)
BARO kPa/Volts 3-5 volts (depends on altitude & baro pressure)
Throttle Position Volts 0.2 - 0.9 (up to 5.0V at wide open throttle)
Throttle Angle 0-100% 0% (up to 100% at wide open throttle)
O2S millivolts 100-1000 (0.1 - 1.0 volt) and varying
Injector pulse width millisec. 1-4 and varying
Spark Advance # of Degrees Varies
Lo Oct. Knock Ret. # of Degrees Varies
S.T. Fuel Trim Counts Varies
L.T. Fuel Trim Counts 58-198
Loop Status 0pen/Closed "Closed Loop" (may go to open after extended idle)
Fuel Trim Cell Cell Number 18-21 at idle (depends on air flow RPM P/N & A/C status)
Knock Retard Degrees of Retard 0
Knock Signal Yes/No No
KS Activity 0-255 Counts 35-50 (usable for DTC 43)
7X Resync Counter 0-255 Counts 0 (usable for DTC 19)
Ign. Control 7X Ref. 0-255 Counts 0-255
Ign. Control 7X Syn. "YES/NO" "YES" (usable for DTC 19 and for misfire diagnosis)
Idle Air Control Counts(steps) 5-60
Park/Neutral Position PN and RDL P - N -- (or -R-DL manual only)
MPH km/h MPH and km/h 0
TCC/Shift Light "ON/OFF" "OFF" ("ON "with TCC commanded "ON")
System Voltage Volts 13.5-14.5
2nd Gear Yes/No (N/A L40 only) No (yes in 2nd or 3rd gear)
3rd Gear Yes/No (N/A L40 only) No (yes in 3rd gear)
A/C Request Yes/No No (yes with A/C requested i.e. selector "ON")
A/C Clutch "ON/OFF" "OFF" ("ON "with A/C commanded "ON")
A/C Ref. Pressure psi/Volts 0-450 psi (varying with high side refrigerant pressure)
Cool Fan Relay "ON/OFF" "OFF" ("ON "with A/C "ON" or hot engine)
Fuel EVAP Purge % 0-100%
QDM "A" Low/Hi Low
QDM "B" Low/Hi Low (High 3T40 Trans Only)
QDM "C" Low/Hi Low
QDM "D" Low/Hi Low
Power Enrichment Yes/No No
P (PRNDL) Low/Hi Low (For 4T60E Trans Only) (Park Only)
A (PRNDL) Low/Hi Low (For 4T60E Trans Only) (Park Only)
B (PRNDL) Low/Hi Hi (For 4T60E Trans Only) (Park Only)
C (PRNDL) Low/Hi Hi (For 4T60E Trans Only) (Park Only)
Trans Range Invalid/Low Drive 2/ Park or Neutral (For 4T60E Transaxle Only)
Drive 3/Drive 4/
Neutral/Reverse/Park
SSA "ON/OFF" "ON" (For 4T60E Transaxle Only)
SSB "ON/OFF" "ON" (For 4T60E Transaxle Only)
Shift Solenoid "A" "ON/OFF" "ON" (For 4T60E Transaxle Only)
Shift Solenoid "B" "ON/OFF" "ON" (For 4T60E Transaxle Only)
TCC Brake Switch Released/Applied Released (For 4T60E Trans Only)
TCC Duty Cycle O-1OO% 0% (For 4T60E Trans Only)
TCC "ON/OFF" "OFF"
Calibration ID # Production PCM/Calibration ID (not usable)
Time From Start Min/Sec Varies (engine run time since start)