FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Description of Parameters






Description of parameters

Parameters, status

General
Certain values deviate from those contained in the signal specifications. This is because read off values are calculated and filtered by the control module. In certain cases the engine must be running to obtain the relevant values.

Gear-shift position sensor position
P/R/N/D/4/3/L = normal gear positions.
OR/OD/OL = Undefined R, D or L positions. The signals from the gear-shift position sensor are outside the normal range but this not interpreted as a fault. This may be because the gear selector is between positions or that the gear-shift position sensor is incorrectly adjusted.
FAULT = the gear-shift position sensor has transmitted the wrong combination of signals and a diagnostic trouble code (DTC) has been stored.

Gear-shift position sensor signal A
LOW = The signal is grounded in the gear-shift position sensor
HIGH = The signal is not grounded in the gear-shift position sensor
Position P: Signal A = LOW
Position R: Signal A = LOW
Position N: Signal A = HIGH
Position D: Signal A = HIGH
Position 3: Signal A = LOW
Position L: Signal A = LOW

Gear-shift position sensor signal B
LOW = The signal is grounded in the gear-shift position sensor
HIGH = The signal is not grounded in the gear-shift position sensor
Position P: Signal B= HIGH
Position R: Signal B = LOW
Position N: Signal B = LOW
Position D: Signal B = LOW
Position 3: Signal B = LOW
Position L: Signal B= HIGH

Gear-shift position sensor signal C
LOW = The signal is grounded in the gear-shift position sensor
HIGH = The signal is not grounded in the gear-shift position sensor
Position P: Signal C= HIGH
Position R: Signal C= HIGH
Position N: Signal C= HIGH
Position D: Signal C= LOW
Position 3: Signal C= LOW
Position L: Signal C= LOW

Gear-shift position sensor signal PA
LOW = The signal is grounded in the gear-shift position sensor
HIGH = The signal is not grounded in the gear-shift position sensor
Position P: Signal C= LOW
Position R: Signal C= HIGH
Position N: Signal C= LOW
Position D: Signal C= HIGH
Position 3: Signal C= LOW
Position L: Signal C= HIGH

Quick shift function from the gear selector module
Applies only to 4T65EV-GT.
The value indicates whether the quick shift mode is selected or not.
ON = Gear selector in position P/R/N/D
ON = Gear selector in Quick shift mode

Quick shift shifting from gear selector module
Applies only to 4T65EV-GT.
The value indicates the quick shift mode which the gear selector module transmits to the transmission control module (TCM).
No shift = no quick shift function
Increase gear = shift up
Decrease gear = shift down

Quick shift status according to transmission control module
Applies only to 4T65EV-GT.
This value indicates the shifting program selected by the control module based on the signal from the gear selector.
Normal = P/R/N/D
Quick shift = Quick shift

Winter mode status
This value indicates the shifting program selected by the control module based on the signal from the mode selector. W = Winter mode.
Engaged = Winter mode engaged
Disengaged = Winter mode disengaged

Current gear (according to gear ratio)
- R, no lock-up
- Gear 1, no lock-up
- Gear 2, no lock-up
- Gear 3, no lock-up
- Gear 4, no lock-up
- Gear 5, no lock-up
- Gear 2, lock-up
- Gear 3, lock-up
- Gear 4, lock-up
- Gear 5, lock-up

New gear (according to solenoids)
- R, no lock-up
- Gear 1, no lock-up
- Gear 2, no lock-up
- Gear 3, no lock-up
- Gear 4, no lock-up
- Gear 5, no lock-up
- Gear 2, lock-up
- Gear 3, lock-up
- Gear 4, lock-up
- Gear 5, lock-up

Shift solenoid status S1
OFF = The solenoid is not activated
ON = The solenoid is activated

Shift solenoid status S2
OFF = The solenoid is not activated
ON = The solenoid is activated

Lock-up solenoid SL status
OFF = The lock-up solenoid is not activated
ON = The lock-up solenoid is activated

Lock-up pressure switch
Applies only to 4T65EV-GT.
The pressure switch is affected by the transmission line pressure. The control module uses the signal from the pressure switch to check whether the lock-up solenoid is activated when the control module has requested lock-up.
OFF = No lock-up activated
ON = Lock-up activated

Stop (brake) lamp switch
The engine control module (ECM) transmits a signal on the Control area network (CAN) indicating whether the stop (brake) lamp switch is activated or not. The transmission control module (TCM) uses the signal to disconnect the lock-up function when braking in order to avoid jolts in the transmission.
OFF = Stop (brake) lamp switch unaffected
ON = Stop (brake) lamp switch affected

Kickdown
The engine control module (ECM) transmits a signal indicating the accelerator pedal (AP) position. During rapid acceleration, with the accelerator pedal (AP) depressed to approximately 87 %, the transmission control module (TCM) receives a signal about kickdown.
OFF = Kickdown is not activated
ON = Kickdown is activated

TCM diagnostic trouble codes (DTCs) status
The value indicates whether there are any diagnostic trouble codes (DTCs) stored in the transmission control module (TCM).
- At least one diagnostic trouble code (DTC) stored
- No diagnostic trouble code (DTC) stored

TCM diagnostic check status
The value indicates whether the transmission control module (TCM) has carried out a complete diagnosis.
- At least one diagnostic test not completed
- All diagnostic tests complete

Parameters, value

Engine speed (RPM)
The engine control module (ECM) transmits the engine speed (RPM) on the Control area network (CAN) from which the transmission control module (TCM) retrieves the signal which it then compares with its own speed sensor signal.
Measurement range: 0 - 8191 rpm
Idling speed: 850 rpm

Transmission speed sensor, input speed
The speed can be generated with the engine idling and the gear selector in P/N position. If the gear selector is in any other position, a gear is engaged and the transmission input shaft is connected to the output shaft and an RPM will not be indicated until the car is driven. Depending on slippage in the torque converter the transmission speed and the engine speed will differ when the lock-up function is not engaged. With lock-up engaged the transmission speed should be the same as engine speed (RPM).
Measurement range (rpm): 0 -
Peak = 14 mA
Trough = 7 mA

TCM speed sensor, calculated speed
The control module receives a signal from the transmission speed sensor which is affected by a toothed pulse wheel and calculates the vehicle speed based on the signal. The speed sensor is an "active" sensor, magnet resistive with a current activated interface ????. The speed is directly proportional to the frequency.
Measurement range: 0 km/h - top speed
Peak = 14 mA
Trough = 7 mA

Vehicle speed ABS
The ABS control module transmits a signal indicating the vehicle speed on the Control area network (CAN) from where the transmission control module retrieves the signal. The transmission control module (TCM) compares it with the signal from the transmission speed sensor.
Measurement range: 0 km/h - top speed
Peak = 14 mA
Trough = 7 mA

Throttle, position
The engine control module (ECM) transmits the accelerator pedal (AP) position on the Control area network (CAN) from where the transmission control module (TCM) retrieves the signal. The signal is used by the transmission to activate the kickdown function.
Measurement range: 0 - 100 %
>87 % = kickdown

Calculated battery voltage
The value indicates the calculated battery voltage at the control module.
Measurement range: 0.0 -25.5 V

Battery voltage
The value indicates battery voltage at the control module.
Measurement range: 0.0 -25.5 V

Oil temperature sensor signal
The value indicates the oil temperature sensor signal. Voltage decreases with increased sensor temperature.
Measurement range: 0.0 - 5.0 V
AW 50-42:
Cold transmission (+20°C): approximately 2.4 V
Hot transmission (+100°C): 0.3 -0.5 V
4T65EV/EV-GT:
Cold transmission (+20°C): ??? V
Warm transmission (+100°C): ??? V

Oil temperature
The transmission control module (TCM) calculates the temperature from the oil temperature sensor signal.
Measurement range: -60 - +180°C

Line pressure solenoid STH amperage
The value indicates the amperage passing through the solenoid circuit. A lower amperage gives a higher reference pressure, which gives a higher line pressure. Solenoid control is directly dependent on the throttle sensor signal. The higher the signal from the throttle sensor the lower the amperage through the solenoid and therefore the higher the line pressure.
Measurement range: 0.0 -1.5 A
Normal value at closed throttle: 280 mA

Line pressure solenoid STH control
Line pressure solenoid STH controls the reference pressure for the transmission. The reference pressure in turn controls the system pressure in the transmission so that the system pressure in gear D varies between 0.28 - 1.2 MPa (R position: 0.5 - 1.8 MPa). Solenoid control is directly dependent on the signal from the throttle position (TP) sensor. The higher the signal from the throttle position (TP) sensor the greater the reference pressure and therefore line pressure.
Measurement range: 0 - 100 %
0 % control, minimal reference pressure, gives lowest line pressure.
100 % control, maximum reference pressure, gives highest line pressure.

Lock-up solenoid SL, amperage
The value indicates the amperage through the solenoid circuit. Control of the solenoid circuit depends on:
- The gear position selected
- Vehicle speed
- The transmission speed - from the transmission speed sensor
- The engine speed (RPM) and load - from the fuel injection system control module
- Throttle opening
- If the brake pedal is depressed - from the stop (brake) lamp switch
- Transmission temperature

Torque control
The control module requests torque-limiting from the engine control module (ECM) in order to limit the torque immediately before shifting to improve shifting quality. The torque is limited by the ignition and fuel injection.
Measurement range: -512 - +512 Nm

Engine torque
The transmission control module (TCM) requests torque-limiting from the engine control module (ECM) in order to limit torque immediately before shifting. The signal is used to inform the ABS control module when the driver has requested torque reduction. This is so that the torque will return to the correct level after reduction.
Measurement range: -512 - +511 Nm
511 = No torque limiting request

Torque reduction when shifting
The transmission control module (TCM) requests torque-limiting from the engine control module (ECM) in order to limit torque immediately before shifting. Torque limiting can occur at three different levels: 25 %, 35 % or 45 %. Limitation lasts for less than 1 second.
0 = No torque limiting requested
25, 35, 45 % = Torque limiting requested

Torque limiting requested
The transmission control module (TCM) requests torque-limiting from the engine control module (ECM) in order to limit torque immediately before shifting. The signal is used to inform the ABS control module when the driver has requested torque reduction. This is so that the torque will return to the correct level after reduction.
Measurement range: -512 - +511 Nm
511 = No torque limiting request

Engine control module (ECM) engine coolant temperature (ECT)
The engine control module (ECM) transmits a signal indicating the engine coolant temperature (ECT) on the Control area network (CAN). The automatic transmission uses the signal to govern lock-up.
Measurement range: -60 - +195°C

Text transmitted to the driver information module
In the event of a service reminder indicator fault, the transmission control module (TCM) transmits a message to the driver information module. The text is displayed in the combined instrument panel display.
1 = TRANSMISSION SERVICE URGENT
2 = TRANSMISSION SERVICE REQUIRED
3 = TRANSMISSION FIX NEXT SERVICE
4 = TRANSMISSION OIL TEMP HIGH
5 = CHANGE TRANS OIL AT NEXT SERVICE