JAGUAR XJ6 1994 2.G Electrical Diagnostic Manual

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

r
P No
1 r
V
ww T
4 - lOnF
)P46 YQ PO(,
PJ (I )P44 Bc
Fig. 1 Fault Codes PO712 / PO713
2
X300 EDM 9 Issue 1 August 1994

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

1 2
JW-1733
Fig. 1 Fault Codes PO721 / PO722
X300 EDM 11 Issue 1 August 1994

w Automatic Transmission (AJ16)
ENGINE SPEED INPUT - P 0726 / P 0727
The engine speed input signal is a square wave output from the ECM. The signal is 12 volt active high with a duty cycle
of 50" / 120" of crankshaft revolution ie 3 pulses per revolution. The frequency of the signal is proportional to engine
speed.
TCM
PI HARNESS ECM
CC007/003 P1063/002 Pl104/022
ENGINE SPEED INPUT CIRCUIT - RANGE / PERFORMANCE P 0726
Engine speed is continuously monitored by the background diagnostics. This fault is flagged if the engine speed ex-
ceeds the maximum speed threshold (approx 6800 rpm). This fault code would suggest an intermittent fault in the cir- cuit.
ENGINE SPEED INPUT CIRCUIT NO SIGNAL - P 0727
If the engine speed drops below 95 rpm and the selected gear is not P or N, then the TCM will initiate the default mode.
This fault code will only be stored if the output speed is greater than 300 rpm. This is to prevent spurious flagging of
codes if the engine stalls.
Possible causes:
. Faulty harness wiring 1 connectors.
. Faulty signal from ECM.
Effects:
. MIL illuminated.
. Transmission warning lamp illuminated.
. Maximum fluid pressure applied.
. Limp home mode applied.
Remedy:
. Repair or renew harness /connectors.
. Examine ECM fault diagnosis (refer to EC Section 1).
Issue 1 August 1994 12 X300 EDM

Automatic Transmission (AJ16)
il
6
P
1
Fig. 1 Fault Codes PO726 1 PO727
X300 EDM 13 Issue 1 August 1994

w Automatic Transmission (AJ16)
SOL ENOlD VALVES
The following tests are performed continuously by a background task. If a fault is detected, it is filtered for a set period.
When filtering ends a fault code is stored in the TCM and action is taken to ensure the integrity of the system.
During limp home mode the internal relay is turned
off to remove the supply to the solenoids and the gearbox with default to fourth gear (if aforward gear is alreadyselected) and third gear (if P.R.N.). Selecting N and then D will engage
3rd gear only.
Each test checks that the feedback from the output stage module is consistent
with the driven state of the solenoid
output, detects short circuit to ground, short circuit to battery voltage and open circuit.
TORQUE CONVERTER CLUTCH SYSTEM - P 0743
PRESSURE CONTROL SOLENOID ELECTRICAL
- P 0748
SHIFTSOLENOID A ELECTRICAL - P 0753
SHIH SOLENOID B ELECTRICAL - P 0758
TCM TRANSMISSION
ccoo7/042 G B003/L
CC007l005 GBOOYH
ccoo7/024 GB003lK
CC007/006 GB003/B
CC007/0 19 G B003/M
TORQUE CONVERTER CLUTCH
SHIFT SOLENOID
A
SHIFT SOLENOID B
PRESSURE CONTROL SOLENOID
SOLENOID SUPPLY
Possible Causes:
. Faulty valve.
Faulty harness wiring /connectors.
Effects:
MIL illuminated.
. Transmission warning lamp illuminated.
Maximum fluid pressure applied.
Limp home mode applied.
Remedy:
Renew valve.
. Repair or renew harness I connector.
Issue 1 August 1994 14 X300 EDM

Automatic Transmission (AJ16) w
mnm
PnW%
wa Wn
1D Int
Fig. 1 Fault Codes PO743 I PO753 I PO758
171- I
1 1
1 L- 2
Fig. 2 Fault Code PO748
X300 EDM 15 Issue 1 August 1994

Automatic Transmission (AJ16)
TORQUE REDUCTION SIGNAL - P 1780
The diagnostic for this signal is based entirely on feedback from the ECM. If the torque reduction request is active for
greater than 2 seconds, the ECM starts the torque reduction fault timeout (IO seconds). If the signal returns to the
standby condition within this time, the timeout is reset. If the timeout matures then the ECM stores a fault code and
transmits 93% on the torque signal line and also lights the MIL where necessary.
The ECM will also initiate the torque reduction fault timeout
if the signal line is permanently high or low for greater
than 125ms. The conditions for resetting the timeout and the actions if the timeout matures are the same as previously
described above. When the TCM receives the correct indication on the torque signal line, this fault code will be stored
and
a substitute function will be adopted and the warning lamp will be illuminated. The engine management will send
normal torque signal when the torque reduction signal returns to standby or when the ignition is reset.
This torque reduction signal is used during gearshifts to conveythe actual amount of retard to be applied to the ignition
advance angle
afterthe other trims. The signal idles at 17% (or 12% if theTCM wishes to drive the MIL on), and changes
to 20% at the start of a gearshift. This represents 0" retard. When an amount of retard is required, the PWM will increase
to the desired value (between 20% and 90%) and return to 20% and then to idle state at the end of the shift.
TCM
PI HARNESS ECM
CC007/032 P1063/008 P1105/026
TORQUE SIGNAL MALFUNCTION - P 1781
The torque signal is a PWM signal from the ECM to the TCM which conveys information about the actual torque devel- oped by the engine in the range 0 to 510Nm. The base frequency is 91Hz and the signal which is active low should be
within the range 10% to 90% modulation. The torque signal is monitored continuously during initialization and oper
- ation. If the frequency of the signal is incorrect or the signal is out of range, then this fault code will be flagged. The
TCM will adopt a substitute function and the warning lamp will be illuminated. This fault code will only be flagged if the engine speed is above 448 rpm.
TCM
PI HARNESS ECM
CC007/02 1 P1063/007 PI 105/033
Possible causes:
. Faulty harness wiring I connector.
. Faulty signal from ECM.
Effects:
. Transmission warning lamp illuminated.
Substitute torque signal adopted by TCM.
. =Normal mode only available.
. No kickdown facility.
. Maximum fluid pressure applied.
Remedy:
. Repair or renew harness / connector.
Examine ECM fault diagnosis (refer to EDM, section 5.1).
Issue 1 August 1994 16 X300 EDM

Automatic Transmission (AJ16)
6
10
B
1
d8-1756
Fig. 1 Fault Codes PI780 / PI781
X300 EDM 17 Issue 1 August 1994