at-150 NISSAN X-TRAIL 2001 Service Repair Manual

AT-150
[EURO-OBD]
DTC P0734 A/T 4TH GEAR FUNCTION
ON BOARD DIAGNOSTIC LOGIC
This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by TCM as
follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is much lower than the position (4th) supposed by TCM, the slip ratio will be much
less than normal. In case the ratio does not reach the specified value, TCM judges this diagnosis malfunction.
This malfunction will be caused when shift solenoid valve A is stuck open or shift solenoid valve B is stuck
closed.
*: P0734 is detected.
And also, this malfunction will be caused when line pressure is lower than normal same as line pressure sole-
noid valve stuck open.
DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION PROCEDURE
CAUTION:
●Always drive vehicle at a safe speed.
●If conducting this “DTC CONFIRMATION PROCEDURE”
again, always turn ignition switch “OFF” and wait at least 5
seconds before continuing.
●Be careful not to rev engine into the red zone on the
tachometer.
NOTE:
If “DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCE-
DURE” has been previously conducted, always turn ignition
switch “OFF” and wait at least 5 seconds before conducting the
next test.
TESTING CONDITION:
Always drive vehicle on a level road to improve the accuracy of
test.
After the repair, perform the following procedure to confirm the mal-
function is eliminated.
Gear position supposed by TCM 1 2 3 4
In case of gear position with no malfunctions 1 2 34
In case of gear position with shift solenoid valve A stuck open2233*
In case of gear position with shift solenoid valve B stuck closed 1 2 21*
Diagnostic trouble code Malfunction is detected when... Check items (Possible cause)
: A/T 4TH GR FNCTN
A/T cannot be shifted to the 4th gear posi-
tion even if electrical circuit is good.
●Shift solenoid valve A
●Shift solenoid valve B
●Line pressure solenoid valve
●Each clutch
●Hydraulic control circuit : P0734
SAT014K
SAT971J