Circuit Description
The 1-2 shift solenoid (SS) valve is a normally-open exhaust valve that, in conjunction with the 2-3 shift solenoid (SS) valve, allows four different shifting combinations. The 1-2 SS valve is attached to the control valve body, within the transmission.
The powertrain control module (PCM) monitors the actual gear ratio, and compares the actual gear ratio with the commanded gear ratio. DTC P0752 sets under two conditions:
| • | A stuck ON 1-2 SS valve |
| • | A stuck ON 1-2 shift valve |
When the PCM detects a 1-1-4-4 shift pattern, then DTC P0752 sets. DTC P0752 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0752 1-2 Shift Solenoid Valve Performance - No Second or Third Gear
Conditions for Running the DTC
| • | No MAP DTCs P0106, P0107, or P0108. |
| • | No TP DTCs P0122 or P0123. |
| • | No OSS DTCs P0502 or P0503. |
| • | No ISS DTCs P0716 or P0717. |
| • | No TCC stuck ON DTC P0742. |
| • | No shift solenoid electrical DTCs P0753 or P0758. |
| • | No TCC electrical DTC P2761. |
| • | The transmission fluid temperature (TFT) is 20-130°C (68-266°F). |
| • | The throttle position (TP) is greater than 8 percent. |
| • | The input speed is 150-6,500 RPM. |
| • | The output speed is greater than 150 RPM. |
| • | The time since the last gear change is greater than 1.0 second. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
Conditions for Setting the DTC
The following occurs twice during the same trip:
| • | The PCM commands 2nd gear and the gear ratio is 2.87:1-3.13:1, 1st gear, for 2 seconds. |
| • | The PCM commands 3rd gear and the gear ratio is 0.61:1-0.71:1, 4th gear, for 3 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits 3-2 downshifts above 52 km/h (32 mph). |
| • | The PCM freezes transmission adaptive 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 P0752 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
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
| • | If you clear DTC P0752, and then cannot reset DTC P0752, inspect for the following conditions: |
| - | Fluid contamination |
| - | Plugged fluid circuits |
| - | Restricted fluid circuits |
| • | Refer to Shift Solenoid Valve State and Gear Ratio . |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step verifies a 1-1-4-4 shift pattern.
-
This step tests for a mechanical or hydraulic condition causing the 1-2 SS valve to be stuck ON, or the circuit to be applied.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||
2 | Did you perform the Transmission Fluid Checking Procedure? | -- | Go to Step 3 | Go to Transmission Fluid Check | ||||||
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. Are current gear and gear ratio within the specified values? | 1st/2nd: 2.87:1-3.13:1 3rd/4th: 0:61:1-0.71:1 | Go to Step 4 | Go to Diagnostic Aids | |||||||
Refer to 1-2 Shift Solenoid Valve Replacement . Did you complete the repair? | -- | Go to Step 5 | -- | |||||||
5 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 6 | Go to Step 2 | ||||||
6 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
