Scan Tool Testing and Procedures
SCAN TOOL DATAPart 1 Of 3:
Part 2 Of 3:
Part 3 Of 3:
As the data values given are standard values estimated on the basis of values obtained from the normally operating vehicles by using a scan tool, use them as reference values. Even when the vehicle is in good condition, there may be cases where the checked value does not fall within each specified data range. Therefore, judgment as abnormal should not be made by checking with these data alone.
Also, conditions in the table that can be checked by the scan tool are those detected by ECM and output from ECM as commands and there may be cases where the engine or actuator is not operating (in the condition) as indicated by the scan tool. Be sure to use the timing light to check the ignition timing.
NOTE:
- With the OBD-II generic scan tool, only star (*) marked data in the table can be read.
- When checking the data with the engine running at idle or racing, be sure to shift M/T gear to the neutral gear position and A/T gear to the "Park" position and pull the parking brake fully. Also, if nothing or "no load" is indicated, turn OFF A/C, all electric loads, PIS and all the other necessary switches.
SCAN TOOL DATA DEFINITIONS
FUEL SYSTEM (FUEL SYSTEM STATUS)
Air/fuel ratio feedback loop status displayed as either open or closed loop. Open indicates that ECM ignores feedback from the exhaust oxygen sensor. Closed indicates final injection duration is corrected for oxygen sensor feedback.
CALC LOAD (CALCULATED LOAD VALUE, %)
Engine load displayed as a percentage of maximum possible load. Value is calculated mathematically using the formula: actual (current) intake air volume / maximum possible intake air volume x 100%.
COOLANT TEMP (ENGINE COOLANT TEMPERATURE, °C, °F)
It is detected by engine coolant temp. sensor.
SHORT FT B1 (SHORT TERM FUEL TRIM, %)
Short term fuel trim value represents short term corrections to the air/fuel mixture computation. A value of 0 indicates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an enleanment correction.
LONG FT B1 (LONG TERM FUEL TRIM, %)
Long term fuel trim Value represents long term corrections to the air/fuel mixture computation. A value of 0 indicates no correction, a value greater than 0 means an enrichment correction, and a value less than 0 implies an enleanment correction.
MAP (INTAKE MANIFOLD ABSOLUTE PRESSURE, kPa, inHg)
It is detected by manifold absolute pressure sensor and used (among other things) to compute engine load.
ENGINE SPEED (rpm)
It is computed by reference pulses from the crankshaft positi6n sensor.
VEHICLE SPEED ( kph , MPH)
It is computed based on pulse signals from vehicle speed sensor in combination meter.
IGNITION ADVANCE (IGNITION TIMING ADVANCE FOR NO.1 CYLINDER, )
Ignition timing of No.1 cylinder is commanded by ECM. The actual ignition timing should be checked by using the timing light.
INTAKE AIR TEMP (°C, °F)
It is detected by intake air temp. sensor and used to determine the amount of air passing into the intake manifold as air density varies with temperature.
MAF (MASS AIR FLOW RATE, gm/s , lb/min)
It represents total mass of air entering intake manifold which is computed based on signals from MAP sensor, IAT sensor, TP sensor, etc.
THROTTLE POS (ABSOLUTE THROTTLE POSITION, %)
When throttle position sensor is fully closed position, throttle opening is indicated as 0 % and 100 % full open position.
OXYGEN SENSOR B1 S1 (HEATED OXYGEN SENSOR-1, V)
It indicates output voltage of HO2S-1 installed on exhaust manifold (pre-catalyst).
OXYGEN SENSOR B1 S2 (HEATED OXYGEN SENSOR-2, V)
It indicates output voltage of HO2S-2 installed on exhaust pipe (post-catalyst). It is used to detect catalyst deterioration.
DESIRED IDLE (DESIRED IDLE SPEED, rpm)
The Desired Idle Speed is an ECM internal parameter which indicates the ECM requested idle. If the engine is not running, this number is not valid.
TP SENSOR VOLT (THROTTLE POSITION SENSOR OUTPUT VOLTAGE, V)
The Throttle Position Sensor reading provides throttle valve opening information in the form of voltage.
INJ PULSE WIDTH (FUEL INJECTION PULSE WIDTH, msec.)
This parameter indicates time of the injector drive (valve opening) pulse which is output from ECM (but injector drive time of No.1 cylinder for multiport fuel injection).
IAC FLOW DUTY (IDLE AIR (SPEED) CONTROL DUTY, %)
This parameter indicates current flow time rate within a certain set cycle of IAC valve (valve opening rate) which controls the amount of bypass air (idle speed).
TOTAL FUEL TRIM (%)
The value of Total Fuel Trim is obtained by putting values of short Term Fuel Trim and Long Term Fuel Trim together. This value indicates how much correction is necessary to keep the air/fuel mixture stoichiometrical.
BATTERY VOLTAGE (V)
This parameter indicates battery positive voltage inputted from main relay to ECM.
CANIST PURGE DUTY (EVAP CANISTER PURGE FLOW DUTY, %)
This parameter indicates valve ON (valve open) time rate within a certain set cycle of EVAP purge solenoid valve which controls the amount of EVAP purge. 0% means that the purge valve is completely closed while 100% is a fully open valve.
CLOSED THROTTLE POSITION (ON/OFF)
This parameter will read ON when throttle valve is fully closed, or OFF when the throttle is not fully closed.
FUEL CUT (ON/OFF)
ON :Fuel being cut (output signal to injector is stopped)
OFF : Fuel not being cut
RADIATOR FAN (RADIATOR FAN CONTROL RELAY, ON/OFF)
ON : Command for radiator fan control relay operation being output.
OFF : Command for relay operation not being out- put.
ELECTRIC LOAD (ON/OFF)
ON : Headlight, small light, heater fan or rear window defogger ON signal inputted.
OFF : Above electric loads all turned OFF
A/C SWITCH (ON/OFF)
ON : Command for A/C operation being output from ECM to A/C amplifier.
OFF : Command for A/C operation not being output.
CANIST AIR VALVE (EVAP CANISTER AIR VALVE, ON/OFF)
ON : ON command being output to EVAP canister air valve.
OFF : ON command not being output.
TANK PRES SOL (FUEL TANK PRESSURE CONTROL SOLENOID VALVE, ON/OFF)
ON : ON command being output to tank pressure control solenoid valve.
OFF : ON command not being output.
FUEL TANK PRESS (FUEL TANK PRESSURE, mmHg)
This parameter indicates the pressure in the fuel tank expressed with respect to the barometric pressure. When it is equal to the barometric pressure, it is indicated as 0 mmHg.
FUEL TANK LEVEL (%)
This parameter indicates approximate fuel level in the fuel tank. As the detectable range of the fuel level sensor is set as 0 to 100%, however, with some models whose fuel tank capacity is smaller, the indicated fuel level may be only 70% even when the fuel tank is full.
PNP SIGNAL (PARK/NEUTRAL POSITION SIGNAL, PIN RANGE or D RANGE)
It is detected by signal from TCM.
D range : A/T is in "R", "D","Z"or "L" range.
P/N range : A/T is in "P" or "N" range or the above signal is not inputted from TCM.
EGR VALVE (%)
This parameter indicates opening rate of EGR valve which controls the amount of EGR flow.
PSP SWITCH (POWER STEERING PRESSURE SWITCH, ON/OFF)
ON : PSP switch detects P/S operation. (high PS pressure)
OFF : PSP switch not detects P/S operation.