Engine Scan Data Values

The data stream scan values, listed below, are typical for the test parameters of a Tech-1 scanner or equivalent scan tool connected to the Data Link Connector (DLC) (formerly the ALDL) diagnostic connector, and under the following conditions:

Engine running at idle/closed throttle
Lower Radiator Hose Hot
Park or Neutral
System operating in "closed-loop."
Accessories "OFF."

Many of the parameters show "data" rather than voltage or resistance values, and cannot be read using a volt/ohm meter.


SCAN POSITION UNITS DISPLAYED TYPICAL DATA VALUE
Engine Speed RPM ± 100 RPM from desired idle
Desired Idle RPM PCM commanded (based on temperature)
Eng Coolant Temp °C/°F 85°-105°C (185°-221°F)
Intake Air Temp °C/°F 10°-90°C (50°-194°F)
(Depends on underhood temperature)
MAP kPa/Volts 29 - 35 kPa (Varies with altitude)
BARO kPa/Volts 70 - 100 kPa/3.5-4.5 volts (Varies with altitude)
Throttle Position Volts 0.3 - 0.9
Throttle Angle Percent (%) 0%
Left HO2S Bnk 1 Millivolts (mV) 10-1000 mV and varying
Loop Status Open/Closed Closed Loop
Right HO2S Bnk 2 Millivolts 10-1000 mV and varying
Loop Status Open/Closed Closed Loop
ST Fuel TR Bnk 1 Counts Varies
LT Fuel TR Bnk 1 Counts 118-138
ST Fuel TR Bnk 2 Counts Varies
LT Fuel TR Bnk 2 Counts 118-138
Fuel Trim Cell Cell Number 16 to 18 (depends on Air Flow and RPM)
Fuel Trim Enable No/Yes Yes
Spark Advance # of Degrees Varies (PCM controlled)
Mass Air Flow Grams per Second Varies
Knock Retard Degrees of Retard 0
Knock Signal No/Yes No(Yes, when detonation is detected)
Lo Res. Signal Milliseconds Varies
High Res. Signal Yes/No Yes
Inj. Pulse Width Bnk 1 Milliseconds 1-4, may vary
Inj. Pulse Width Bnk 2 Milliseconds 1-4, may vary
Idle Air Control Counts 5 - 50
Learned IAC Counts 5 - 50
EGR Duty Cycle Percentage 0%
System Voltage Volts 12.0 - 14.5
AIR Control Off/On Off
Fuel EVAP Purge Percentage 0%
Injector Fault No/Yes No
TCS/ASR Active No/Yes No
Fan 1 Fan 2 Off/On Off/On Depends on A/C refrigerant pressure and Engine coolant temperature
A/C Request No/Yes No
A/C Clutch Off/On Off
A/C Status Off/On Off
A/C Refig Pressure PSI, Volts Varies (Depends on temp)
TCC Temp Sw Open/Closed Open
Park/Neutral Pos Park/Neutral, Reverse
Drive 4, Drive 3,
Drive 2, Low, Park/Neutral
Invalid
Park/Neutral Pos P-N--/-R-DL Park/Neutral(P-N-)
TCC Brake Switch Closed/Open Closed
TCC Solenoid Off/On Off
TCC PWM Solenoid Off/On Off
1 - 2 Shift Sol Off/On On
2 - 3 Shift Sol Off/On On
Eng or Trans DTC Yes/No No
Knock Sensors OK/One Open/Both
Open/Grounded OK
Time From Start Hrs/Min/Sec Varies