4T45-E Automatic Transaxle
DTC P0751 (3.5L)
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 P0751 sets under two conditions:
^ A stuck OFF 1-2 SS valve
^ A stuck OFF 1-2 shift valve
When the PCM detects a 2-2-3-3 shift pattern, then DTC P0751 sets. DTC P0751 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0751 1-2 Shift Solenoid (SS) Valve Performance - No First or Fourth Gear
Conditions for Running the DTC
^ No MAF DTCs P0101, P0102 or P0103.
^ No MAP DTCs P0107 or P0108.
^ No TP DTCs P0120 or P0220.
^ No VSS 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 engine is running for 5 seconds or more and not in fuel cut off.
^ The transmission fluid temperature is between 20°C (68°F) and 130°C (266°F).
^ The TP indicated angle is 8 percent or more.
^ The transmission OSS is 200 RPM or more.
^ The engine torque is greater than 50 Nm (37 ft. lbs.).
^ The input speed is 150 - 6,000 RPM.
^ The time since the last gear change is 1.0 second.
Conditions for Setting the DTC
The following occurs twice during the same trip:
^ The PCM commands 1st gear and the gear ratio is 1.54:1-1.71:1, 2nd gear, for 2 seconds.
^ The PCM commands 4th gear and the gear ratio is 0.91:1-1.07:1, 3rd gear, for 4 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 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 P0751 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 P0751, and then cannot reset DTC P0751, 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.
3. This step verifies a 2-2-3-3 shift pattern.
4. This step tests for a mechanical or hydraulic condition causing the 1-2 SS valve to be stuck OFF, or the circuit to be released.
