Engine 4 Data

Engine Scan Tool Data Definitions
This information will assist you in tracking down emission or driveability problems since the displays can be viewed while the vehicle is being driven. Refer to the Powertrain OBD System Check for additional information. Testing and Inspection

Engine Speed - Range (0 - 16384 RPM): Engine Speed is computed by the VCM from the fuel control reference input. It should remain close to the desired idle under various engine loads with the engine idling.

Desired Idle - Range (0 - 3187 RPM): The idle speed that is commanded by the VCM. The VCM will compensate for various engine loads to maintain the desired idle speed.

IAC Position - Range (0 - 255): The Idle Air Control (IAC) pintle position commanded from the VCM is displayed in counts. The greater the number of counts, the greater the command idle speed (air passages opened). Idle air control should respond fairly quickly to changes in engine load to maintain desired idle RPM.

Desired IAC - Range (0 - 255): This indicates the desired AC position.

Inj. Avg. Bank 1 - Range (0 - 499 ms): Indicates the injector ON time that is commanded by the VCM.

Inj. Avg. Bank 2 - Range (0 - 499 ms): Indicates the injector ON time that is commanded by the VCM.

Engine Load - Range (0 - 100%): This indicates the engine load based on Manifold Absolute Pressure. The higher the percentage, the more load the engine is under.

MAF - Range 0 - 512 g/s: The VCM converts the Mass Air Flow sensor input signal into grams per second, indicating the amount of air entering the engine.

Throttle Position (TP) Sensor - Range (0 - 5.0V): The Throttle Position (TP) Sensor is used by the VCM to determine the amount of throttle demanded by the operator of the vehicle. The TP sensor will read between 0.36 - 0.96V at idle to above 4V at Wide Open Throttle (WOT).

TP Angle - Range (0 - 100%): The TP Angle is computed by the VCM from the TP signal voltage input. TP Angle should read 0% at idle (TP voltage below 0.90V) and read 100% at Wide Open Throttle (WOT).

Manifold Absolute Pressure (MAP) Sensor - Range (0 - 5.0V): The MAP sensor produces a low signal voltage when manifold pressure is low (high vacuum) and a high voltage when the pressure is high (low vacuum). With the ignition ON and the engine stopped, the manifold pressure is equal to atmospheric pressure causing the signal voltage to be high. This information is used by the VCM as an indication of vehicle altitude and is referred to as BARO. Comparison of this BARO reading with a known good vehicle with the same sensor is a good way to check accuracy of a suspect sensor. Readings should be the same ±4V.

Barometric Pressure (BARO) - Range (0 - 5.0V): The BARO represents a measurement of barometric air pressure that is determined by using the Manifold Air Pressure (MAP) sensor to determine manifold vacuum. Since barometric air pressure depends on altitude, it may vary from 100 kPa (sea level) to 60 kPa (14,000 ft.)

Manifold Absolute Pressure (MAP) - Range (10 kPa - 104 kPa): The Manifold Absolute Pressure (MAP) sensor measures the change in the intake manifold pressure from engine load and speed changes. As intake manifold pressure increases, the air density in the intake manifold also increases and additional fuel is required.

Barometric Pressure (BARO) Sensor - Range (0 kPa - 62 kPa): The BARO reading displayed is determined from the MAP sensor at ignition ON, engine OFF, and WOT conditions. The BARO reading displayed represents barometric pressure and is used to compensate for altitude differences. EVAP Duty Cycle - Range (0 - 100%): Indicates the EVAP canister purge solenoid duty cycle that is being commanded by the VCM.

EGR Duty Cycle - Range (0 - 100%): Indicates the EGR duty cycle that is being commanded by the VCM.

Actual EGR Position - Range (0 - 100%): Indicates the actual EGR position in percentage.

Desired EGR Position - Range (0 - 199.9%): Indicates the desired EGR position in percentage.

EGR Sensor - Range (0 - 5.00V): Indicates the actual EGR position in voltage.

Cam Retard - Range (2039 to -2040): Indicates the amount of Camshaft Position sensor to Crankshaft Position sensor off set.

Spark Advance - Range (-96° to -255°): This is a display of the spark advance calculation which the VCM is programming into the ignition system. It computes the desired spark advance using data such as engine temperature, RPM, load, vehicle speed and operating mode.

KS Retard - Range (0 - 90°): This indicates the amount of spark advance being removed to diminish spark knock.

DTC Counter - Range (0 - 255): This indicates the total number of current Diagnostic Trouble Codes (DTCs) set. This does not necessarily mean the Malfunction Indicator Lamp (MIL) is illuminated.

Engine Run Time - Range (0:00:00 - 18:12:15) Hours: Minutes: Seconds: This is a measure of how long the engine has been running during this ignition cycle. When the engine stops running, the timer is reset to zero.