This information will assist in emission or driveability problems. The displays can be viewed while the vehicle is being driven. Always perform the Diagnostic System Check-Engine Controls first. The Diagnostic System Check will confirm proper system operation.

Actual Fuel Rail Pressure-MPa/PSI: Indicates the current fuel rail pressure, as measured by the fuel rail pressure (FRP) sensor.

Ambient Air Temperature: Indicates the temperature of the air outside of the engine, around the vehicle.

Accelerator Pedal Position (APP) Angle-Range 0-100 Percent: Computed by the engine control module (ECM) from APP voltage, throttle position (TP). The scan tool should display 0 percent at idle and 100 percent at wide open throttle (WOT).

Accelerator Pedal Position (APP) Sensor 1-3-Range 0-5 Volts: The engine control module (ECM) uses the APP sensor to control fuel delivery as requested by the driver.

Balancing Rate Cyl. 1-8: This indicates the adjustment of fuel volume to individual cylinders. The measurement will be negative if fuel volume is lowered, and positive if volume is raised.

Barometric pressure (BARO)-Range 10-105 kPa: The barometric pressure (BARO) reading is determined by the BARO sensor located inside the ECM. The BARO reading display represents barometric pressure and is used to compensate for altitude differences.

Basic Fuel Rate: This indicates the basic commanded fuel rate from the ECM. The ECM adjusts this based on sensor inputs.

Basic PC valve on Time: This indicates the basic PC Valve on Time commanded by the ECM.

Battery Voltage-Range 12-14 Volts: This represents the system voltage measured by the engine control module (ECM) at the battery voltage feed circuit.

Boost Pressure Sensor-Range 10-200 kPa: The amount of turbo boost pressure in the intake manifold. True boost pressure is determined by subtracting barometric pressure (BARO) from the actual reading.

Crank Signal Present: Indicates if the crankshaft position (CKP) sensor signal is being received by the engine control module (ECM).

Cylinder Balance Mode: This indicates the cylinder balance mode in which the ECM is currently operating.

Diagnostic Switch: Indicates the current state of the diagnostic switch.

Desired Fuel Rail Pressure-Range 37-40 MPa: Indicates the fuel rail pressure desired by the engine control module (ECM) based on current sensor inputs. This can be compared the actual fuel rail pressure to determine sensor accuracy or fuel pressure problems.

Desired Idle Speed-Range 0-3187 RPM: The idle speed that is requested by the engine control module (ECM). The ECM will compensate for various engine loads based on engine coolant temperature (ECT) to keep the engine at the desired speed.

End of Split Injection: Indicates at what RPM split injection ends. Varies with load and other conditions.

ECT Engine Coolant Temperature -Range -40 to +151°C ( -40 to +304°F): The engine coolant temperature (ECT) sensor sends a signal to the engine control module (ECM) relative to ECT. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold and internal resistance is high, the ECM monitors a high signal voltage. The ECM interprets the high signal voltage as a cold engine. As the sensor warms and internal resistance decreases, the voltage signal will decrease and the ECM will interpret the lower voltage as a warm engine.

Engine Run Time-Range 00:00:00 (HRS/MIN/SEC): A measure of how long the engine has been operating. When the ignition is cycled to OFF, the value is reset to zero.

Engine Speed-Range 0-9999 RPM: Engine speed is computed by the engine control module (ECM) from the crankshaft position (CKP) sensor. If the CKP sensor is inoperative, an RPM reading is taken from the injection pump cam signal. The reading should remain close to desired idle under various engine loads with the engine idling. Engine speed value is very accurate.

Engine Start Mode: This indicates the engine start mode by the ECM.

Engine Stop Switch: Indicates the current commanded status of the engine stop switch.

Exhaust Brake Switch: Indicates the current commanded status of the exhaust brake switch.

Final Fuel Rate: This indicates the actual fuel rate as calculated by the ECM. The ECM attempts to adjust this rate to bring it close to the basic fuel rate.

Flow Limiter 1-6: These indicate the operation time of each flow damper, as commanded by the ECM.

Fuel Rate Correction: This indicates the adjustment of the final fuel rate to the basic fuel rate by the ECM.

Fuel Rate at Start: Indicates the startup fuel rate.

Fuel Rate at Max Speed: Indicates the fuel flow through the injectors at maximum engine speed.

Fuel Temperature Sensor-Range -28 to +140°C (-18 to +285°F): A thermistor is located in the optical sensor. The thermistor determines fuel temperature. When the sensor is cold and internal resistance high, the engine control module (ECM) monitors a high signal voltage. The ECM interprets the voltage as low fuel temperature. As the sensor warms and internal resistance is low, the voltage signal will decrease, and the ECM will interpret the low voltage as warm fuel.

ISC Fuel Rate Correction: This indicates the fuel rate correction for engine idling by the ECM.

ISC Fuel Rate Integral: This indicates the integral fuel rate at engine idling by the ECM.

ISC Fuel Rate Proportion: This is the fuel rate correction for the engine idling by the ECM.

Injection Control Mode: Indicates the commanded state of the fuel injectors by the engine control module (ECM).

Injection Pump Signal Present: Indicates if the injection pump, cam sensor, signal is present.

Main Injection Interval: Indicates the commanded on time of the fuel injector for the main injection pulse.

Main Injection Timing: Indicates the current timing of the main injection pulse.

Maximum Fuel Temperature: Indicates the maximum fuel temperature as indicated by the fuel temperature sensor.

Neutral Switch: Indicates the current status of the neutral switch.

Overheat Number of Times: Indicates the number of times the engine coolant temperature (ECT) sensor has indicated an overheat condition.

Overspeed Number of Times: Indicates the number of times the engine RPM has been run overspeed.

Pilot Injection Interval: Indicates the commanded on time for the pilot injection pulse.

Pump Control Mode: Indicates the commanded state of the injection pump by the engine control module (ECM).

Pressure Control (PC) Valve Close Interval: Indicates the timing of the pressure control valve closure by the engine control module (ECM).

Pressure Control (PC) Valve Delay Time: This indicates the PC valve delay time between commanded and actual On time, as measured by the ECM.

Pressure Control (PC) Valve Feedback: This indicates the calculated PC valve on time.

Pressure Control (PC) Valve On Time: Indicates the commanded ON time of the pressure control valve by the engine control module (ECM).

Pressure Control (PC) Valve On Time Length: Indicates the number of degrees rotation that the pressure control (PC) valve is ON. This is controlled by a mechanical cam in the injection pump, and by electrical commands from the engine control module (ECM).

Split Fuel Rate: Indicates the quantity of fuel being injected during each small split injection pulse.

Split Injection Interval: Indicates the time between split injection pulses. Used during slow cranking engine for startup.

Starter Switch: Indicates the commanded state of the starter switch.