DESCRIPTION The ECM uses
signals from the output speed sensor SP2 and input speed sensor NT to
detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).
Then the ECM compares the actual gear with the shift schedule in the ECM
memory to detect mechanical problems of the shift solenoid valves,
valve body and automatic transmission (clutch, brake, gear, etc.). |
DTC Code | DTC Detection Condition |
Trouble Area | | P0729 |
- 6th gear shift malfunction:
- The ECM determines there is a malfunction when both of the following conditions are met (2-trip detection logic):
(a) When the ECM directs the transmission to switch to 5th gear, the actual gear is shifted to 5th.
(b) When the ECM directs the transmission to switch to 6th gear, the actual gear is shifted to 4th. |
- Valve body is blocked or stuck (sequence valve)
- Shift solenoid valve SLT remains open or closed
- Automatic transmission (clutch, brake, gear, etc.)
|
HINT:
MONITOR DESCRIPTION The
ECM commands gear shifts by turning the shift solenoid valves ON/OFF
and switching oil pressure to the valves in the valve body. This
DTC indicates that the sequence valve is locked in the direction the
spring stretches and that shifting to 6th gear is impossible. MONITOR STRATEGY |
Related DTCs | P0729: Gear 6 incorrect ratio (Sequence valve) / Functional check | |
Required sensors/Components | Sequence valve | |
Frequency of operation | Continuous | |
Duration | 0.4 seconds | |
MIL operation | 2 driving cycles | |
Sequence of operation | None | TYPICAL ENABLING CONDITIONS All |
The monitor will run whenever the following DTCs are not present |
P0717 (Turbine speed sensor circuit) P0722 (Output speed sensor circuit)
P0710, P0712, P0713, P2740, P2742, P2743 (ATF temperature sensor circuit)
P0973, P0974 (Shift solenoid valve S1 circuit) P0976, P0977 (Shift solenoid valve S2 circuit)
P0979, P0980 (Shift solenoid valve S3 circuit) P0982, P0983 (Shift solenoid valve S4 circuit)
P0985, P0986 (Shift solenoid valve SR circuit) P0748 (Shift solenoid valve SL1 circuit)
P0778 (Shift solenoid valve SL2 circuit) P0115, P0116, P0117, P0118, P011B (ECT (Engine coolant temperature) sensor circuit)
P0327, P0328, P032C, P032D (KCS sensor circuit) | |
ETCS (Electric Throttle Control System) |
Not system down | | Transmission position |
"D" | | Duration time from shifting "N" to "D" |
4 seconds or more | | ECT |
40°C (104°F) or higher | | Spark advance from max. retard timing by KCS control |
0° crankshaft angle or more | |
Engine | Starting | |
Calculated load value | 7.75% or more (A/C off)
7.75% or more (A/C on) | | Input speed/output speed (NT/NO)
NT: Input (Turbine) speed NO: Internal counter shaft speed |
3.30 to 7.50 or 1.91 to 2.35 or 1.28 to 1.53
or 0.93 to 1.07 or 0.65 to 0.79 or
0.51 to 0.65 | Condition (A) |
ECM selected gear | 5th | | Vehicle speed |
2 km/h (1.2 mph) or more | | Throttle valve opening angle |
5% or more at 2000 rpm (Conditions vary with engine speed) | Condition (B) |
ECM selected gear | 6th | | Vehicle speed |
2 km/h (1.2 mph) or more | | Throttle valve opening angle |
5% or more at 2000 rpm (Conditions vary with engine speed) | TYPICAL MALFUNCTION THRESHOLDS
Both of the following conditions are met: Condition (A) and (B) Condition (A) |
Turbine speed / Output speed (NT / NO) | 0.65 or more, and 0.79 or less
(This means actual gear is 5th) | Condition (B) |
Turbine speed / Output speed (NT / NO) | 0.93 or more, and 1.07 or less
(This means actual gear is 4th) | CAUTION / NOTICE / HINT
NOTICE: Perform the universal trip to clear permanent DTCs (See page
 ). PROCEDURE
| 1. |
CHECK DTC OUTPUT (IN ADDITION TO DTC P0729) |
(a) Connect the Techstream to the DLC3. (b) Turn the ignition switch to ON.
(c) Turn the Techstream on. (d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(e) Read the DTCs using the Techstream. Result |
Result | Proceed to | |
Only P0729 is output |
A | | P0729 and other DTCs are output |
B | HINT: If any other codes besides P0729 are output, perform troubleshooting for those DTCs first.
| B |
 | GO TO DTC CHART |
|
A |
 | |
| 2. |
PERFORM ACTIVE TEST USING TECHSTREAM (RUNNING TEST) |
HINT: Using
the Techstream to perform Active Tests allows relays, VSVs, actuators
and other items to be operated without removing any parts. This
non-intrusive functional inspection can be very useful because
intermittent operation may be discovered before parts or wiring is
disturbed. Performing Active Tests early in troubleshooting is one way
to save diagnostic time. Data List information can be displayed while
performing Active Tests. (a) Warm up the engine. (b) Turn the ignition switch off.
(c) Connect the Techstream to the DLC3. (d) Turn the ignition switch to ON.
(e) Turn the Techstream on. (f) Enter the following menus: Powertrain / Engine and ECT / Active Test.
(g) According to the display on the Techstream, perform the Active Test.
HINT: While driving, the shift position can be forcibly changed with the Techstream. Engine and ECT |
Tester Display | Test Part |
Control Range | Diagnostic Note | |
Control the Shift Position | Operate shift solenoid valves and set each shift position |
- Press "→" button: Shift up
- Press "←" button: Shift down
| Possible to check operation of the shift solenoid valves.
[Vehicle Condition] 50 km/h (30 mph) or less |
HINT:
- This test can be conducted when the vehicle speed is 50 km/h (30 mph) or less.
- The 4th to 5th and 5th to 6th up-shifts must be performed with the accelerator pedal released.
- The 6th to 5th and 5th to 4th down-shifts must be performed with the accelerator pedal released.
- Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.
- The shift position commanded by the ECM is shown in the Data List display on the Techstream.
- Gear positions in the event of a solenoid valve mechanical problem:
|
Tester gear shift command |
1st |
2nd |
3rd |
4th |
5th |
6th |
|
Actual gear position under malfunction |
1st |
2nd |
3rd |
4th |
5th |
4th |
OK: Gear position changes in accordance with the tester command.
| NG |
| REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY |
|
OK | |
| |
| 3. |
PERFORM ACTIVE TEST USING TECHSTREAM (SHIFT SOLENOID VALVE SLT) |
NOTICE:
- Perform the test while the ATF temperature is 50 to 80°C (122 to 176°F).
- Be careful to prevent the hose of SST from interfering with the exhaust pipe.
- Perform the test with the A/C off.
HINT: Using
the Techstream to perform Active Tests allows relays, VSVs, actuators
and other items to be operated without removing any parts. This
non-intrusive functional inspection can be very useful because
intermittent operation may be discovered before parts or wiring is
disturbed. Performing Active Tests early in troubleshooting is one way
to save diagnostic time. Data List information can be displayed while
performing Active Tests. |
(a) Remove the test plug from the center of the right side of the transmission case and connect SST. |
|
SST: 09993-19015 09993-00010 09993-00040 (b) Connect the Techstream to the DLC3.
(c) Start the engine and warm it up. (d) Measure the line pressure with SST.
(e) Turn the Techstream on. (f) Enter the following menus: Powertrain / Engine and ECT / Active Test.
(g) According to the display on the Techstream, perform the Active Test.
(h) Measure the line pressure. Engine and ECT |
Tester Display | Test Part |
Control Range | Diagnostic Note | |
Activate the Solenoid (SLT)* | Operate the shift solenoid SLT and raise line pressure |
ON or OFF
HINT:
- OFF: Line pressure up (when Active Test "Activate the Solenoid (SLT)" is performed, ECM commands SLT solenoid to turn off)
- ON: No action (normal operation)
| [Vehicle Condition]
- Vehicle stopped
- Engine idling
| HINT: *:
Activate the Solenoid (SLT) in the Active Test is performed to check
the line pressure changes by connecting SST to the automatic
transmission, which is used in the Hydraulic Test (See page
) as well. Please note that the pressure values in the Active Test and Hydraulic Test are different.
OK: The line pressure changes as specified when performing the Active Test. Text in Illustration
| NG |
| REPLACE SHIFT SOLENOID VALVE SLT |
|
OK | |
| |
| 4. |
CLEAR DTC AND PERFORM RUNNING TEST | (a) Clear the DTC (See page
). (b) Check for the DTC again after conducting the Monitor Drive Pattern (See page
). OK: No DTC code output.
| OK |
| END |
| NG |
| REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY | | 
