Automatic Transmission (AJ16) w
8.1.1 ZF 4HP 24 E TRANSMISSION, SYSTEM DESCRIPTION
The electronic transmission system fitted to normally aspirated 4.0 liter vehicles comprises the following components:
0 ZF 4HP 24 E Automatic Transmission
0 Rotary selector switch
0 Electronic Transmission Control Module
0 Decoder Module
0 Performance Mode Switch
0 Kickdown Switch
0 Gear Selection Illumination Module
System control is effected by the transmission control module (TCM), located behind the passenger side fascia, which
continuously monitors requests made by the drivervia the gearselector, throttle pedal etc. This data is used
inconiunc- tion with the speed input from the transmission and inputs from the engine management system, to calculate optimum
shift points and control parametersfor shift pressure and ignition retardation to enhance shift quality and reduce trans-
mission unit wear.
TheTCM is also able to detect faults within the system and store the relevant fault codes for interrogation with diagnos-
tic equipment.
Gear shifts are controlled by three solenoid valves, and
a pressure control regulator, located on the valve block within
the transmission unit assembly. If a serious fault occurs, the TCM removes all electrical power from these valves and
the transmission system reverts to a mechanical default condition. This condition allows only mechanical selection
of reverse and one forward gear, either third or fourth, depending on prevailing conditions at the time of the default.
The decoder module receives inputs from the rotary switch and decodes these to drive one of six possible outputs,
illuminating the correct gear indicator on the gear selector illumination module.
The performance mode switch and kick
-down switch are used to adjust transmission operation as required by the
driver. Performance mode selection, made via a switch mounted on the gear selector mechanism surround, can be
either NORMAL, for everyday use, or SPORT, for enhanced performance. Kick
-down is activated by a switch mounted
below the accelerator pedal and is used to initiate a downward gear change, increasing torque and acceleration.
8.1.2 COMPONENT DESCRlPTIONS
Transmission Unit
The ZF 4HP 24 E automatic transmission unit houses the three solenoid valves which control gear shifts. A pressure
control valve is also located on the solenoid valve block. These four valves initiate and control shift patterns within
the transmission unit by regulating fluid flow.
Rotary Selector Switch
The seven position rotary gear selector switch is mounted on the LH side of the transmission unit and indicates gear
selection to the TCM and decoder module.
Transmission Control Module
The electronic transmission control module regulates gear changes by controlling the operation of the transmission
unit solenoid valves, and monitoring the state of other vehicle systems which have an effect on torque demand, vehicle
speed etc. The module also interfaces with the engine management system, climate control system, body processor
unit and ABS
I traction control system.
Connections from the TCM are listed on the following page.
X300 EDM 1 Issue 1 August 1994
IW Automatic Transmission (AJ16)
TRANSMISSION FLUID TEMPERATURE SENSOR INPUTS P 0712 / P 0713
The transmission fluid temperature sensor is a positive temperature coefficient thermistor bead, located in the internal
wiring harness of the transmission assembly and immersed in the transmission fluid in the unit sump. The wiring is
taken out through the transmission connector and runs through the rotary switch and then into the gearbox harness
to the TCM. The pin outs on the relevant parts are as follows.
TCM ROTARY SWITCH TRANSMISSION
55 WAY CONNECTOR 12 WAY MULTI-LOCK 9 PIN DEUTSCH
(CC007) (GB002) (GB003)
PIN 46 - SIGNAL PIN 8 -SIGNAL PIN D -SIGNAL
PIN
44 -GROUND PIN 9 - GROUND PIN J -GROUND
TRANSMISSION FLUID TEMPERATURE SENSOR LOW INPUT- P 0712
This input is continuously monitored during initialization and operation by the processor and is checked against spe- cific limits to be in range. If the temperature indicated by the sensor is too low then this fault code will be stored and
the processor will use a substitute value for the transmission oil temperature.
The low limit is approximately
-50" C. This fault would indicate that the output signal line (Pin 46) is probably short
circuit to ground.
TRANSMISSION FLUID TEMPERATURE SENSOR HIGH INPUT- P 0713
This input is continuously monitored during initialization and operation by the processor and is checked against spe- cific limits to be in range. If the temperature indicated by the sensor is too high then this fault code will be stored and
the processor will use a substitute value for the transmission oil temperature. The high limit is approximately 185" C.
This fault would indicate that the input signal line (Pin 46) is probably open circuit or short circuit to battery positive
voltage (+I2 nominal).
Possible causes:
. Faulty sensor.
. Faulty harness wiring or connection to sensor.
Effects:
. Substitute oil temperature adopted by TCM.
Remedy:
Renew internal harness.
. Repair or renew harness I connectors.
Issue 1 August 1994 8 X300 EDM
Automatic Transmission (AJ16)
OUTPUT SPEED SENSOR - P 0721 / P 0722
The output speed sensor is located on the rear of thevalve block assembly inside the transmission. Connection is made
via pins A and F of the %way transmission connector located on the left hand side of the transmission assembly. The
wiring runs through the rotary switch harness and the vehicle gearbox harness to the TCM on pins 2 and 38 of the 55 way multi-plug. These wires are shielded by a screen which is terminated on pin 20 of the TCM multi-plug. The sensor
detects the motion of the output shaft via a 36 toothed wheel.
TCM ROTARY SWITCH TRANSMISSION
(CC007) (GB002) (GB003)
PIN 2 -SIGNAL PIN 11 -SIGNAL PIN F -SIGNAL
PIN 38
- GROUND PIN 12 -GROUND PIN
A - GROUND
OUTPUT SPEED SENSOR CIRCUIT RANGE/ PERFORMANCE - P 0721
This test is only performed when a downshift takes place and therefore the vehicle must be in a forward gear ie D, 3, 2, 1. A fault will be flagged if the engine speed is above a threshold which is dependant on the shift and the state of the lock up clutch.
This fault code would suggest that there is an intermittent fault in the circuit.
OUTPUT SPEED SENSOR CIRCUIT NO SIGNAL - P 0722
The background diagnostic software continuously monitors the output speed and flags this fault if the output speed
is zero when the engine speed is greater than 2000 rpm and a forward gear, D, 3,2,1, is selected.
This fault code would suggest
a permanent fault, either open circuit, short to ground or short circuit to battery positive
voltage (+12V nominal).
Possible causes:
Faulty sensor.
Faulty harness wiring I connectors.
Effects:
MIL illuminated.
Transmission warning lamp illuminated.
Maximum pressure applied.
Limp home mode applied.
Remedy:
Renew sensor.
Repair or renew harness I connectors. ~~~~ ~~
Issue 1 August 1994 10 X300 EDM
Automatic Transmission (AJ16) w
8.1.5
nector.
TRANSMISSION CONNECTOR
(GB003)
TRANSMISSION ELECTRICAL PIN POINT TESTS
THE FOLLOWING TESTS describe methods of testing the transmission control solenoid valves from the multi-pin con-
0 A = Road Speed Sensor
0 B = Pressure Regulator
0 D = Oil Temperature Signal
0 F = Road Speed Sensor
0 H = MVI Solenoid
0 J = Oil Temperature Ground
0 K = MV2 Solenoid
0 L = MWVK Solenoid
0 M = Solenoid Supply
The solenoid valves are located on the valve block in the transmission assembly and can be identified by their position.
Connection is made via a connector located on the LHS of the transmission assembly.
Impedance Checks
M
-L)
M
-K) 28-60ohm
0 M-H)
M-B 5-70hm
M)(A
K)(D
L 1-( F O/C
H)(J
B)(
L-K)
L
- H ) 56- 120 ohm
K
-H)
L
-B)
K
-B) 33-67ohm
H
-B)
All Pins
- Ground OK
5
m- 1738
Fig. 1 Transmission Multi-plug Connector
X300 EDM 27 Issue 1 August 1994
Automatic Transmission (V12) Powertrain
8.2.1 POWERTRAIN
41-80-E TRANSMISSION, SYSTEM DESCRIPTION
The electronic transmission system fitted to 6.0 liter and 4.0 liter super-charged vehicles comprises the following com- ponents:
0 Hydra-matic 4L-80-E Automatic Transmission
0 Electronic Transmission Control Module
0 Performance Mode Switch
0 Kickdown Switch
0 Gear Selection Module (illuminated)
System control is effected by the transmission control module
(TCM), located behind the passenger side fascia, which continuously monitors requests made bythe driver via the gearselector, throttle pedal etc. This data is used inconjunc- tion with the speed input from the transmission and inputs from the engine management system, to calculate optimum
shift points and control parametersfor shift pressure and ignition retardation to enhance shift quality and reduce trans- mission unit wear.
TheTCM is also able to detect faults within the system and store the relevant fault codes for interrogation with diagnos- tic equipment.
Gear shifts are controlled
by three solenoid valves, and a pressure control regulator, located on the valve block within
the transmission unit assembly. If a serious fault occurs, the TCM removes all electrical power from these valves and
the transmission system reverts to a mechanical default condition. This condition allows only mechanical selection
of reverse and one forward gear, either
third or fourth, depending on prevailing conditions at the time of the default.
The performance mode switch and kick
-down switch are used to adjust transmission operation as required by the
driver. Performance mode selection, made via a switch mounted on the selector switch surround, can be either NOR- MAL, for everyday use, or SPORT, for enhanced performance. Kick-down is activated by a switch mounted below the
accelerator pedal and is used to initiate a downward gear change, increasing torque and acceleration.
8.2.2 COMPONENT DESCRIPTIONS
Transmission Unit
The powertrain 4L-80-E transmission unit houses the two solenoid valves which control gear shifts. A pressure control
valve is also located on the solenoid valve block. These three valves initiate and control shift patterns within the trans- mission unit by regulating fluid flow.
Performance Mode Switch
The two position performance mode switch allows selection of 'sport' or 'normal' mode as required by the driver. The
switch input to TCM causes a gear shift pattern change so that gear shifts take place at higher engine revs, enhancing
performance, when in 'sport' mode. For everyday use, 'normal' mode utilises a shift pattern for optimum driver com- fort.
Kickdown Switch
The 'kick-down' facility is activated when full downward travel of the accelerator pedal occurs.
Activation of the switch provides a signal to TCM indicating that greater acceleration, and hence downward gear shifts
are required. Switch height is adjustable
so that kick-down can be achieved at a pre-determined throttle opening.
Gear Selection Illumination Module
This module is located above the gear selector mechanism and its sole purpose is to display the selected gear (in red)
on receipt of a signal from the decoder module.
X300 EDM 1 Issue 1 August 1994
Automatic Transmission (V12) Powertrain
8.2.3 OPERATING PRlNClPL ES
The electronic control system is split into four main functional areas:
0 Shift Point Control
0 Lock-up Control
0 Pressure Modulation
0 Engine Torque Control
0
Shift Point Control
The optimum gear ratio is selected as a function of transmission output speed, engine load, position of selector switch
and program switch.
Lock-up Control
The torque converter clutch is engaged as a function of load, output speed, gear selected and drive program. Lock-up
is possible in second, third and fourth gear. Apply and release quality is controlled by the pulse width modulated pres-
sure regulator solenoid.
Pressure Modulation
Hydraulic pressure in the transmission shift friction elements is accurately matched to transmission output torque
using an electrically operated solenoid valve to control pressure level. Transmission input torque is calculated from
an output torque value, supplied by EMS, and converter slip.
Engine Torque Control
Engine torque control reduces the energy dissipated within the system during gear shifts. The effect of this control
increase the transmission service life by reducing slippage time, increases comfort by reducing clutch torque trans- mission and allows a greater transfer of power by the transmission unit.
8.2.4 INPUTS / OUTPUTS
8.2.4.1 INPUTS
Transmission Range
The transmission range is detectec ,ythe pressureswitch manifold located within the transmission unit. The manifold
transmits a coded message to the TCM indicating gear selector position.
Performance Mode Select
Performance mode select uses a two wire input to the TCM allowing selection of different transmission operating
modes.
Line A; Used for selection of traction control shift pattern and controlled
by the ABS /TC CM.
Line
B; Used for selection of 'Normal' or 'Sports' mode, manually selected at a two position rocker switch mounted
on the gear selector unit. Switch resistance is equal to or greaterthan look$, open circuit and equal to or less than 0.5$ closed circuit, measured across contacts at a current of 10mA.
Kickdown Switch
This signal is controlled by the operation ofthe kickdown switch on depression of the accelerator pedal to its full extent.
The switch remains in 'normally open' position until contact with the pedal closes the contacts. Switch resistance is
equal to or greater than look$, open circuit, and equal to or less than 0.5$ closed circuit, measured across contacts at
a current of
10Ma.
Calibration Select
The calibration select input allows identification of different vehicle specifications, ie 4.0 liter supercharged, or 6.0 liter (V12). The link, to ground, from the TCM is either short or open circuit, dependant upon internal software calibration
for each vehicle variant.
X300 EDM 5 Issue 1 August 1994
Automatic Transmission (V12) Powertrain
Engine Speed
The engine speed is provided by an open collector signal supplied from the engine management control module
(ECM).
Throttle Position
This signal, from the ECM, performs the following two functions:
1.
2.
Engine Torque (and warm-up)
This signal, from the ECM, performs the following three functions:
1. During cranking to convey the completion of an engine warm
-up cycle to TCM.
2. To convey engine torque information, under normal running conditions, to TCM.
3. To convey engine torque fault signals to TCM.
Engine ‘warm
-up’ cycle commences from ignition ON until 500ms after the engine exceeds 400rpm. After this time
delay either an engine torque, or torque fault signal will be transmitted.
Transmission Input Speed
The transmission input speed sensor is mounted within the transmission housing and produces a variable frequency
signal, directly proportional to forward clutch housing rotational speed which is transmitted to the TCM. Sensor resis- tance equals 1.25kQ f 0.25.
Transmission Output Speed
The transmission output speed sensor is mounted within the transmission housing and produces a variable frequency
signal, directly proportional to the rear carrier rotational speed which is transmitted to the TCM. Sensor resistance
equals
1.25w2 + 0.25.
hake Application
When a brake application signal is received, due to brake switch operation, the torque convertor clutch lock-up sole- noid is de-energized, releasing lock-up mode if already applied
Transmission Oil Temperature
The transmission oil temperature sensor, located within the internal harness, monitors oil temperature and transmits a corresponding signal to the TCM.
To convey throttle position information to the TCM.
To indicate fault conditions between ECM and throttle potentiometer.
8.2.4.2 OUTPUTS
Gear Shift Solenoids
The two gear shift solenoids, located within the transmission housing, determine gear ratio when the selector is in any
of the forward gear positions.
Force Motor
The force motor, mounted within the transmission housing acts as a transmission torque fluid pressure regulator.
Torque Converter Clutch (TCC) Solenoid
The torque converter clutch solenoid, mounted within the transmission housing, provides a direct drive from the en- gine, via the converter clutch, to the driven wheels, giving the efficiency of a manual gearbox. The solenoid also pro- vides a ’ramp‘ apply and release to engage / disengage the clutch gently.
0
0
0
e
X300 EDM Issue 1 August 1994 6
0
0
0
Brakes (
12.1 COMPONENT LOCATlONS
Fig. 1 AJ16 (normally aspirated)
Fig.
2 AJ16 (supercharged)
Fig.
3 VI2
Key to Figs. 1,2 and 3:
1. Throttle position sensor 4. ABS motor
2. Traction control actuator 5. Valve block 3. Pump 6. Control module (ABS / TC CM)
X300 EDM 1 Issue 1 August 1994