Circuit Description
The 2-3 shift solenoid (SS) valve controls the fluid flow acting on
the 2-3 shift valves. The 2-3 SS valve is a normally-open exhaust
valve that is used with the 1-2 SS valve in order to allow four different
shifting combinations.
When the PCM detects a 1-2-2-1 shift pattern, then DTC P0757
sets. DTC P0757 is a type A DTC.
Conditions for Running the DTC
• | No TP sensor DTCs P1120 or P1220. |
• | No VSS assembly DTCs P0502 or P0503. |
• | No TCC solenoid valve DTC P0740. |
• | No TCC stuck ON DTC P0742. |
• | No 1-2 SS valve DTC P0753. |
• | No 2-3 SS valve DTC P0758. |
• | No 3-2 SS valve assembly DTC P0785. |
• | No TFP manual valve position switch DTC P1810. |
• | No TCC PWM solenoid valve DTC P1860. |
• | The engine speed is greater than 450 RPM for 5 seconds. |
• | The engine is not in fuel cutoff. |
• | The TP angle is greater than 10 percent. |
• | The transmission fluid temperature is 20-130°C (68-266°F). |
• | The system voltage is 10-18 volts. |
• | The transmission output speed is 150 RPM or greater. |
Conditions for Setting the DTC
DTC P0757 sets if both of the following conditions occur:
Condition 1
• | The PCM commands third gear for 1 second. |
• | The estimated gear ratio is 1.6-1.8. |
• | Speed ratio is 0.5 or greater. |
• | The engine torque is 68-542 N·m (50-400 lb ft). |
• | All conditions are met for 2 seconds. |
Condition 2
• | The PCM commands fourth gear for 1 second. |
• | The estimated gear ratio is 1.8-3.3. |
• | Speed ratio is 0.5 or greater. |
• | The engine torque is 0-542 N·m (0-400 lb ft). |
• | All conditions are met for 2 seconds. |
Action Taken When the DTC Sets
• | The PCM illuminates the malfunction indicator lamp (MIL). |
• | The PCM commands third gear only. |
• | The PCM commands maximum line pressure. |
• | The PCM inhibits TCC engagement. |
• | The PCM inhibits 4th gear if in hot mode. |
• | The PCM freezes transmission adapt functions. |
• | The PCM records the operating conditions when the Conditions for
Setting the DTC are met. The PCM stores this information as Freeze Frame
and Failure Records. |
• | The PCM stores DTC P0757 in PCM history. |
Conditions for Clearing the MIL/DTC
• | The PCM turns OFF the MIL during the third consecutive trip in
which the diagnostic test runs and passes. |
• | A scan tool can clear the MIL/DTC. |
• | The PCM clears the DTC from PCM history if the vehicle completes
40 warm-up cycles without an emission-related
diagnostic fault occurring. |
• | The PCM cancels the DTC default actions when the ignition switch
is OFF long enough in order to power down the PCM. |
Diagnostic Aids
• | Verify that the transmission meets the specifications in the
Shift Speed
table. |
Test Description
The number below refers to the step number on the diagnostic table.
-
This step tests that the PCM commanded all
shifts, that all shift solenoid valves responded correctly, but that all
the shifts did not occur.
DTC P0757
Step
| Action
| Value(s)
| Yes
| No
|
1
| Did you perform the Powertrain Diagnostic System Check?
| --
| Go to
Step
2
| Go to
Diagnostic System Check - Engine Controls
in Engine Controls
|
2
|
- Install a scan tool.
- Turn ON the ignition, with the engine OFF.
Important: Before clearing the DTC, use the scan tool in order to record the Freeze
Frame and Failure Records. Using the Clear Info function erases the Freeze
Frame and Failure Records from the PCM.
- Record the DTC Freeze Frame and Failure Records.
- Clear the DTC.
- Drive the vehicle in D4 range under the following conditions:
Accelerate the vehicle, ensuring that the PCM commands 1st, 2nd,
3rd and 4th gears.
Did you detect a 1-2-2-1 shift pattern?
| --
| Go to
Step 3
| Go to Diagnostic Aids
|
3
| Inspect the shift solenoid/hydraulic circuit for the following
conditions:
• | An internal malfunction |
• | Damaged seals on the shift solenoid valve |
Did you find and correct the condition?
| --
| Go to
Step 4
| --
|
4
| Perform the following procedure in order to verify the repair:
- Select DTC.
- Select Clear Info.
- Drive the vehicle in D4 range under the following conditions,
only if traffic and road conditions permit:
Hold the throttle
at 15% and accelerate to 80 km/h (55 mph).
- Select Specific DTC.
- Enter DTC P0757.
Has the test run and passed?
| --
| System OK
| Go to
Step 1
|