AT-146
[RE4F04B]
DTC P0734 A/T 4TH GEAR FUNCTION
Revision: November 2006
2006 Altima
DTC P0734 A/T 4TH GEAR FUNCTION
PFP:31940
Description
ECS0097O
●
This is an OBD-II self-diagnostic item and not available in TCM self-diagnosis.
●
This malfunction will not be detected while the A/T check (position) indicator lamp is indicating another
self-diagnosis malfunction.
●
This malfunction is detected when the A/T does not shift into fourth gear position or the torque converter
clutch does not lock up as instructed by the TCM. This is not caused by electrical malfunction (circuits
open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve
operation, malfunctioning oil pump or torque converter clutch, etc.
CONSULT-II REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Specification data are reference values.
On Board Diagnosis Logic
ECS0097P
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 B is stuck closed.
Gear positions supposed by TCM are as follows.
In case of gear position with no malfunctions: 1, 2, 3 and 4 positions
In case of gear position with shift solenoid valve B stuck closed: 1, 2, 2 and 1* positions to each gear position
above
*: P0734 is detected.
Diagnostic trouble code A/T 4TH GR FNCTN with CONSULT-II or P0734 without CONSULT-II is detected
when A/T cannot be shifted to the 4th gear position even if electrical circuit is good.
Possible Cause
ECS0097Q
Check the following items.
●
Shift solenoid valve A
●
Shift solenoid valve B
●
Line pressure solenoid valve
●
Each clutch
●
Hydraulic control circuit
Diagnostic Trouble Code (DTC) Confirmation Procedure
ECS0097R
CAUTION:
●
Always drive vehicle at a safe speed.
●
If conducting this “DTC CONFIRMATION PROCEDURE” again, always turn ignition switch OFF
and wait at least 10 seconds before continuing.
●
Be careful not to rev engine into the red zone on the tachometer.
Gear position
1
2
3
4
Shift solenoid valve A
ON (Closed)
OFF (Open)
OFF (Open)
ON (Closed)
Shift solenoid valve B
ON (Closed)
ON (Closed)
OFF (Open)
OFF (Open)
Monitor item
Condition
Specification
Torque converter clutch
solenoid valve duty
Lock-up OFF
↓
Lock-up ON
Approximately 4%
↓
Approximately 94%
Line pressure solenoid
valve duty
Small throttle opening (Low line pressure)
↓
Large throttle opening (High line pressure)
Approximately 24%
↓
Approximately 95%
