For 1990-2009 cars

PARAMETER | DEFINITION | TABLE
--- | --- | ---
A/C HIGH SIDE PRESSURE | Indicates air conditioning high side absolute pressure based on the A/C pressure sensor signal voltage at the ECM. This parameter is used to control A/C relay and cooling fan(s) operation. Pressure is a conversion from voltage. | 0
A/C PRESSURE SENSOR | Indicates the A/C pressure sensor signal voltage at the ECM based on air conditioning absolute high side pressure. | 0
A/C RELAY COMMAND | Displays ON if the ECM is commanding the A/C relay On. | 0, 1, 6
A/C REQUEST | Displays YES if the ECM received an A/C request from the BCM over the CAN serial data link. The BCM receives the input from the HVAC control head via the A/C On/Off switch. The BCM will not send a request if the evaporator temperature is too low. | 0, 6
APP AT FULL POSITION | Displays YES if the ECM is detecting the accelerator pedal position (APP) sensor 1 at 100%. | 6
APP AT IDLE | Displays YES if the ECM is detecting the accelerator pedal position (APP) sensor 1 at 0%. | 6
APP SENSOR 1 | Indicates the accelerator pedal position (APP) sensor signal voltage at the ECM from APP sensor 1. APP sensor 1 and 2 are housed in one assembly. | 0, 2, 6
APP SENSOR 2 | Indicates a redundant accelerator pedal position (APP) sensor signal voltage at the ECM from APP sensor 2. APP sensor 2 voltage is scaled half of sensor 1. APP sensor 1 and 2 are housed in one assembly. | 0, 2, 6
BATTERY VOLTAGE | Indicates battery voltage at the battery voltage supply to the ECM. This voltage is referenced to ECM case ground. | 0, 1, 2, 3, 4, 5, 6, 7
BRAKE SWITCH (STOP LAMP SWITCH) | Displays APPLIED when the brake pedal is being depressed (switch closed). Input is used for TCC and cruise control engage/disengage. | 0, 6
CMP ACTIVE COUNTER | Indicates the equivalent decimal value from an 8 bit binary input based off the camshaft sensor. The ECM monitors the camshaft signal for 16 engine revolutions. Within the 16 crankshaft revolutions, a cam pulse should be seen every other crankshaft revolution. So, a pattern of 10101010 (which converts to 170 decimal), or a pattern of 01010101 (which converts to 85 decimal) is normal. Any number other than 85 or 170 indicates a cam signal error. | 0, 3
COOLING FAN SPEEDS | Indicates the Off, Low, Medium or High cooling fan speeds that the ECM is commanding to the cooling fan control module. NOTE: Both cooling fans will always run at the SAME speed. The ECM controls the ground for 2 logic circuits, fan control 1 and 2, to the cooling fan control module. Off = both circuits ungrounded, LOW = fan control 2 grounded and fan control 1 ungrounded, MED = fan control 1 grounded and fan control 2 ungrounded and HIGH = both circuits grounded. | 1
CRUISE BRAKE SWITCH | Displays APPLIED when the brake pedal is being depressed (switch open). Input is used for cruise control engage/disengage. | 0, 6
CRUISE RESUME/ACCEL | Displays ON if the RESUME/ACCEL switch is being pressed. | 0, 6
CRUISE SET/COAST | Displays ON if the SET/COAST switch is being pressed. | 0, 6
CRUISE SWITCH | Displays ON if the CRUISE ON/OFF switch is turned On (pressed in). | 0, 6
DESIRED IDLE SPEED | Indicates the idle engine speed the ECM is commanding. Desired idle speed is based on ECT, transaxle range switch position and A/C On/Off. | 6
ECT | Indicates the temperature of the engine coolant based on the ECT sensor signal voltage at the ECM. Temperature is a conversion from voltage. | 0, 1, 2, 3, 4, 5, 6, 7
EGR DUTY CYCLE | Indicates the percentage of EGR solenoid on-time the ECM is commanding. A duty cycle (DC) of 100% indicates the EGR valve is held open. NOTE: The valve will not move unless a 40% or greater D.C. is being commanded. | 0, 1, 2, 3, 5, 6
EGR SENSOR | Indicates the value of the EGR sensor signal voltage at the ECM. This voltage is a representation of the EGR pintle position. | 0, 5
ENGINE AT OPERATING TEMPERATURE | Displays YES if the ECT indicates to the ECM that the engine coolant temperature is greater than 80°C (176°F). | 2
ENGINE LOAD | Engine load value is calculated by the ECM based on engine speed and MAF sensor values. | 0, 1, 2, 3, 4, 5, 6, 7
ENGINE OIL LIFE LEFT | Percentage of engine oil life left based on engine revolutions, ECT and vehicle mileage. At 5% engine oil life left, the ECM will send a message to the BCM over the CAN serial data link. The BCM will in turn send a message to the I/P cluster over the Class II serial data link to turn On the CHANGE OIL SOON telltale. | 0
ENGINE RUN TIME | Indicates the amount of time the engine has been running since the ignition was turned On. | 0, 1, 2, 3, 4, 5, 6, 7
ENGINE SPEED | Indicates the crankshaft speed in revolutions per minute as indicated by the ECM based on the crankshaft position (CKP) sensor. The CKP sensor works in conjunction with a 58 tooth reluctor wheel on the crankshaft to produce an AC voltage of different amplitude and frequency. | 0, 1, 2, 3, 4, 5, 6, 7
EVAP PURGE SOLENOID DC | Indicates the EVAP purge solenoid On-time the ECM is commanding. A duty cycle (DC) of 100% indicates the EVAP purge valve is held open. NOTE: The valve will not move unless a 40% or greater D.C. is being commanded. | 1, 2, 5
EVAP VENT SOLENOID | Displays On if the ECM is commanding the EVAP vent solenoid On (closed valve, no EVAP system venting). | 1, 5
FAN CONTROL 1 COMMAND | Displays On if the ECM is grounding the fan control 1 circuit. This logic output is used by the ECM in conjunction with FAN CONTROL 2 to command the cooling fan control module to run the cooling fans at a given speed. | 1
FAN CONTROL 2 COMMAND | Displays ON if the ECM is grounding the fan control 2 circuit. This logic output is used by the ECM in conjunction with FAN CONTROL 1 to command the cooling fan control module to run the cooling fans at a given speed. | 1
FUEL LEVEL | Indicates the level of fuel in the fuel tank based on the fuel level sensor signal voltage at the ECM. The percentage on Scan tool, is a conversion from voltage. | 0, 2, 3, 4
FUEL LEVEL SENSOR | Indicates the fuel level sensor signal voltage at the ECM based on the fuel level in the fuel tank. | 0, 2, 3
FUEL PUMP RELAY COMMAND | Displays ON if the ECM is commanding the fuel pump relay On. | 1
FUEL TANK PRESS. SENSOR | Indicates the fuel tank pressure sensor signal voltage at the ECM based on the difference between the outside air pressure and internal fuel tank vapor pressure. Normal readings with the fuel cap Off should be within 2.35-2.85 volts or at near zero vacuum based on outside air pressure. | 0, 5
FUEL TANK PRESSURE | Indicates the vapor pressure above the fuel in the fuel tank based on the fuel tank pressure sensor signal voltage at the ECM. | 0, 5
GENERATOR L TERMINAL | Displays the actual voltage state on the generator L-terminal that the ECM is detecting. LOW should be read with the ignition On and engine Off. As soon as the engine is started and the generator begins to charge, the generator will unground the generator L-terminal circuit and the display should read HIGH. | 0
HO2S BANK 1 SENSOR 1 | Displays a lambda value which indicates the actual air/fuel ratio of bank 1 (cyl. 1, 3, 5) the sensor is detecting. Lambda is denoted as the actual air fuel ratio divided by 14.7 to 1. A lambda of 1.00 indicates that the actual air fuel ratio of bank 1 is 14.7 to 1. | 0, 2, 5
HO2S BANK 1 SENSOR 2 | Indicates the voltage across the heated oxygen sensor (HO2S) bank 1 sensor 2 detected at the ECM HO2S bank 1 sensor 2 inputs. A bias voltage of 421-479 from the ECM should be read when the sensor is cold. Normal operating ranges will remain fairly steady around 500-800 mV when the vehicle is at normal operating temperature under steady cruise. | 0, 2, 5
HO2S BANK 2 SENSOR 1 | Displays a lambda value which indicates the actual air/fuel ratio of bank 2 (cyl 2, 4, 6) the sensor is detecting. Lambda is denoted as the actual air fuel ratio divided by 14.7 to 1. A lambda of 1.00 indicates that the actual air fuel ratio of bank 2 is 14.7 to 1. | 0, 2, 5
HO2S BANK 2 SENSOR 2 | Indicates the voltage across the heated oxygen sensor (HO2S) bank 2 sensor 2 detected at the ECM HO2S bank 2 sensor 2 inputs. A bias voltage of 421-479 from the ECM should be read when the sensor is cold. Normal operating ranges will remain fairly steady around 500-800 mV when the vehicle is at normal operating temperature under steady cruise. | 0, 2, 5
HO2S HEATER BN 1 SEN 1 HO2S HEATER BN 1 SEN 2 HO2S HEATER BN 2 SEN 1 HO2S HEATER BN 1 SEN 1 | Displays ON if the ECM is commanding the HO2S bank 1 or 2 sensor 1 or 2 heater On. NOTE: The ECM will pulse the heater under certain temperature and driving conditions. | 1, 2
HO2S HEATER BN 1 SEN 1 HO2S HEATER BN 2 SEN 1 | Indicates an averaged HO2S bank 1 or 2 sensor 1 heater feedback voltage at the ECM. Normal values will fluctuate greater than 1 volt with engine running when heater is pulsing. Note: The voltage the ECM reads is divided through a resistor network. The Scan tool will display near 4.7 volts when heater is Off (high voltage), 2.1 volts when heater is On (low voltage) and near 2.5 volts when an open circuit occurs. | 2
HO2S HEATER BN 1 SEN 2 HO2S HEATER BN 2 SEN 2 | Indicates a calculated average heater element ohm value based off of the HO2S bank 1 or 2 sensor 2 heater feedback voltage at the ECM. Normal values will range between 20-40 ohms. If a circuit fault occurs, the ohm value will count up. Note: The value may read 0.00 for up to 5 minutes after engine has been started to ensure the sensor has fully warmed up. | 2
IAT | Indicates the temperature of the air entering the engine based on the IAT sensor signal voltage at the ECM. Temperature is a conversion from voltage. The IAT sensor is an integral part of the mass air flow (MAF) sensor. | 0, 1, 2, 3, 4, 5, 6, 7
IGNITION ON | Displays YES if the ECM detects voltage on the ignition 1 input. | 0
INJECTOR PULSE WIDTH | Indicates the average base fuel injector On-time the ECM is commanding. | 2
INTAKE MANIFOLD RUNNER CONTROL (IMRC) SOLENOID | Displays On if the ECM is commanding the IMRC solenoid On. The solenoid allows controlled vacuum to pull up on a diaphragm, which controls the intake runner divider. The ECM moves this divider under higher engine loads to increase volumetric efficiency. | 1
KNOCK CONTROL BANK 1 OR 2 | Displays ACTIVE if the ECM is in a knock control event based on the knock sensor A/C signal voltage at the knock sensor inputs of the ECM. | 3
KNOCK RETARD CYL 1-6 | Indicates the amount of spark retard the ECM is commanding from the normal calculated spark advance. This is in response from knock sensor 1 or knock sensor 2 AC signal voltage detected. The ECM has the ability to retard timing on individual cylinders. | 3
KNOCK SENSOR 1 OR 2 | Indicates an amplified knock sensor AC signal voltage at the ECM. The greater the voltage level, the greater the noise the sensor is detecting. NOTE: The normal knock sensor 1 voltage at idle from bank 1 will be around 3.25 volts with knock sensor 2 voltage from bank 2 around 1.25 volts. The difference is due to different frequency filtering from each bank. | 0, 3
LOOP STATUS BANK 1 | Displays CLOSED if the ECM is controlling fuel based on the HO2S bank 1 sensor 1. Displays OPEN if the ECM is controlling fuel based solely on engine speed, APP, MAF, ECT and IAT sensor inputs. | 2
LOOP STATUS BANK 2 | Displays CLOSED if the ECM is controlling fuel based on the HO2S bank 2 sensor 1. Displays OPEN if the ECM is controlling fuel based solely on engine speed, APP, MAF, ECT and IAT sensor inputs. | 2
LOOP STATUS BN 1 SEN 2 | Displays CLOSED if the HO2S bank 1 sensor 2 is at operating temperature and is capable of providing feedback for catalyst testing and certain fuel control techniques. | 7
LOOP STATUS BN 2 SEN 2 | Displays CLOSED if the HO2S bank 2 sensor 2 is at operating temperature and is capable of providing feedback for catalyst testing and certain fuel control techniques. | 7
LOW OIL PRESSURE | Displays YES if the engine oil pressure is low (switch closed, circuit grounded). | 0
LT FT BN 1 OR 2 - CRUISE/ACCEL. | Indicates an averaged fuel correction factor from the short term fuel trim values during moderate to heavy engine loads (cruise above 80 km/hr [50 mph] or acceleration) based on the HO2S bank 1 or 2 sensor 1 signal. Nominal values should be near 0% correction. A positive percentage indicates the ECM is adding fuel to the specific bank to maintain a 14.7 to 1 air/fuel ratio. A negative percentage indicates the ECM is decreasing fuel to the specific bank to maintain a 14.7 to 1 air/fuel ratio. | 2, 5
LT FT BN 1 OR 2 - IDLE /DECEL | Indicates an averaged fuel correction factor from the short term fuel trim values during very low engine load conditions (idle and deceleration) based on the HO2S bank 1 or 2 sensor 1 signal. Nominal values should be near 0% correction. A positive percentage indicates the ECM is adding fuel to the specific bank to maintain a 14.7 to 1 air/fuel ratio. A negative percentage indicates the ECM is decreasing fuel to the specific bank to maintain a 14.7 to 1 air/fuel ratio. | 2, 5
MAF | Indicates intake air flow passing through the MAF sensor based on the MAF sensor signal voltage at the ECM. | 0, 1, 2, 3, 4, 5, 6, 7
MAF SENSOR | Indicates MAF sensor signal voltage at the ECM based on the airflow passing through the MAF sensor. | 0, 1, 2, 3, 4, 5, 6, 7
MAIN RELAY COMMAND | Displays ON if the ECM is commanding the main relay On. | 1
MAP | Indicates manifold absolute pressure based on the MAP sensor signal voltage at the ECM. This sensor is used for EGR flow test diagnostics and barometric pressure readings. | 0, 1, 2, 3, 4, 5, 6, 7
MAP SENSOR | Indicates the manifold absolute pressure sensor signal voltage at the ECM based on the absolute manifold air pressure. This sensor is used for EGR flow test diagnostics and barometric pressure readings. | 0
MISFIRE CURRENT CYL 1-6 | Indicates current cylinder misfires. The ECM runs 1000 revolution misfire tests which update current misfire counter information. The current counters will be reset to zero once the 1000 revolutions are completed. Important: The maximum value the Scan tool can display is 255. | 4
MISFIRE HISTORY CYL 1-6 | Indicates history cylinder misfires. The ECM runs 1000 revolution misfire tests which update current misfire counter information. The current counters will be reset to zero once the 1000 revolutions are completed. | 4
PARK/NEUTRAL SWITCH | Displays P-N or RDL as indicated from the transaxle range switch. The input is feed into the TCM, which is sent over the CAN serial data link to the ECM. | 6
SHORT TERM FT BANK 1 | Indicates the current fuel correction factor based on the HO2S bank 1 sensor 1 signal. Nominal values should be near 0 percent correction. A positive percentage indicates the ECM is adding fuel to bank 1 to maintain a 14.7 to 1 air/fuel ratio. A negative percentage indicates the ECM is decreasing fuel to bank 1 to maintain a 14.7 to 1 air/fuel ratio. | 2, 5
SHORT TERM FT BANK 2 | Indicates the current fuel correction factor based on the HO2S bank 2 sensor 1 signal. Nominal values should be near 0 percent correction. A positive percentage indicates the ECM is adding fuel to bank 2 to maintain a 14.7 to 1 air/fuel ratio. A negative percentage indicates the ECM is decreasing fuel to bank 2 to maintain a 14.7 to 1 air/fuel ratio. | 2, 5
SPARK | Indicates the number of commanded degrees of spark advance for cylinder 1. A positive number means before TDC and a negative number means after TDC. Note: The ECM can individually control individual cylinder spark advance. | 3
TAC FUEL SHUT OFF | Displays YES if the ECM has entered limp home mode due to a TP sensor 1 circuit error. If this parameter reads YES, the REDUCED POWER telltale will be illuminated and the ECM will either shut fuel Off or enter one of the 2 limp home modes (random injector disable with limited RPM) for the remainder of the ignition cycle even if the fault corrects itself. | 7
TAC LEARN COUNTER | The ECM will perform a throttle body relearn procedure whenever the ignition is turned On, with the engine Off for longer the 29 seconds. The ECM will take about 2-3 seconds to perform TP sensor lower limit measurements and return spring checks. The TAC learn counter will start at 0 and count up to 9 or 11, depending on software update, during the learn procedure. If the counter does not start at 0 or does not count up to 9 or 11, a fault in the TAC system is occurring and a DTC will be set. | 7
TAC LIMIT AUTHORITY | Displays YES if the ECM has entered limp home mode due to an accelerator pedal position (APP) sensor 1 or sensor 2 circuit fault. If this parameter reads YES, the MIL will be illuminated and the vehicle will be in one of the 2 limp-home modes (slow acceleration) for the rest of the ignition cycle even if the fault corrects itself. | 7
TAC LIMIT POWER | Displays YES if the ECM has entered limp home mode due to a throttle actuation error. If this parameter reads YES, the REDUCED POWER telltale will be illuminated and the vehicle in 1 of the 2 limp home modes (random injector disable with limited RPM) for the remainder of the ignition cycle even if the fault corrects itself. | 7
TORQUE DELIVERED | Indicates a commanded duty-cycle percentage signal to the electronic brake and traction control module (EBTCM) used for traction control. This PWM signal equates how much of the calculated engine torque is being delivered to the engine. Under nearly all circumstances, 100% of the calculated engine torque should be applied. One-hundred percent of the engine torque delivered will equate to about an 80-85% signal duty cycle. Therefore, 80-85% should always be read on the Scan tool with engine running normally unless the ECM is reducing torque for another reason other than traction control. | 0
TORQUE REQUESTED | Indicates an actual duty cycle percentage signal to the engine control module (ECM) from the electronic brake and traction control module (EBTCM) used for traction control. This PWM signal equates how much calculated engine torque reduction the EBTCM desires. Under a non-traction control event, 0% reduction of the calculated engine torque should be applied. Zero percent of the engine torque reduction will equate to about 20-25% signal duty cycle. Therefore, 20-25% should always be read on the Scan tool with engine running normally unless a circuit fault on circuit 463 is occurring. If a circuit fault occurs, the Scan tool will read 100% with the engine running. | 0
TP ANGLE | Indicates throttle plate angle based on the TP sensor 1 signal voltage at the ECM. Throttle plate angle is a conversion from voltage. | 0, 1, 2, 3, 4, 5, 6, 7
TP SENSOR 1 | Indicates the TP sensor 1 signal voltage at the ECM. The TP sensor 1 is an integral part of the throttle body assembly. | 0, 2, 6
TP SENSOR 2 | Indicates the TP sensor 2 signal voltage at the ECM. The TP sensor 2 is an integral part of the throttle body assembly. | 0, 2, 6
VEHICLE SPEED | With ABS: The engine control module (ECM) receives vehicle speed from the electronic brake and traction control module (EBTCM) -- ABS module. The EBTCM receives this vehicle speed information from the right wheel speed sensor A/C signal voltage.

Without ABS: The ECM receives vehicle speed from the wheel speed signal conditioner module. The conditioner module receives this vehicle speed from the right front wheel speed sensor A/C signal voltage. The conditioner module converts the A/C voltage from the sensor to a square wave by pulse width modulating the circuit between the ECM and conditioner module to ground. The ECM interprets this square wave as vehicle speed.

NOTE: The speedometer is run off the output speed sensor signal, which is a direct input to the transmission control module (TCM). The TCM sends vehicle speed information over the controller area network (CAN) link to the body control module (BCM). The BCM in turn will send a message over the Class II link to the I/P cluster who will position the speedometer.

0, 1, 2, 3, 4, 5, 6, 7

PARAMETER | DEFINITION
--- | ---
VIN | Displays vehicle identification number.
CALIBRATION ID | Displays an 8-digit number for identifying the engine control calibrations in the ECM. This number should be used to compare against the latest Service Stall System (SSS) calibration. NOTE: You may need to read the TEXT message towards the bottom of the SSS screen to view the latest SSS calibration.
SOFTWARE NO. | Displays 10 plus a 4-digit number for identifying the engine control software in the ECM. The software number in not viewable on the SSS and therefore is not needed by the technician for reprogramming.
ECM PN | Displays an 8-digit number for identifying the engine control hardware/software/calibration configuration in the ECM. This parameter is also known as the End Model Number. This number is used by the assembly plant and represents the latest number the assembly plant is/was using. If a service calibration was released which the assembly plant did not use (old model year updates for instance), then the ECM PN (part number) will not change. Always use the calibration ID in the ECM vs. what is in the SSS to determine what is the latest software/calibration package.