P0751
DTC P0751 Shift Solenoid Performance (1 Of 2):
DTC P0751 Shift Solenoid Performance (2 Of 2):
Shift Solenoid Performance:
Shift Solenoid:
CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) monitors the commanded gear and the speed ratio in order to identify a 1-2 Shift Solenoid Valve (1-2 SS Valve) problem.
When the PCM detects a 2-3 only or a 1-4 only shift pattern, then DTC P0751 sets. DTC P0751 is a type B DTC.
CONDITIONS FOR SETTING THE DTC
^ No Throttle Position (TP) DTCs P0122 or P0123.
^ No Vehicle Speed Sensor (VSS) DTC P0502.
^ No Torque Converter Clutch (TCC) stuck ON DTC P0742.
^ No 1-2 solenoid electrical DTC P0753.
^ No 2-3 solenoid electrical DTC P0758.
^ No TCC Pulse Width Modulated (PWM) solenoid electrical DTC P1860.
^ No TCC enable solenoid electrical DTC P1864.
^ The engine speed is greater than 500 RPM for 5 seconds.
^ Not in fuel shut off.
^ The vehicle speed is greater than 8 km/h (5 mph).
^ The transmission temperature is 30-150°C (86-302°F).
^ The transmission range switch indicates D4.
^ The traction control is not active.
^ All of the above must occur twice and either fail-cases 1,2,3 and 4 or 1,2,3 and 5 are true twice.
FAILURE CRITERIA
CASE 1:
^ 1-2 shift commanded
^ The throttle position is 14-45% and is constant within 5%.
^ The vehicle speed is 8-80 km/h (5-50 mph).
^ When 2nd gear is commanded and within 2.6 seconds, engine speed is 100 RPM greater than the engine speed of the commanded 1st gear.
CASE 2:
^ 2-3 shift commanded
^ The throttle position is 14-45% and is constant within 5%.
^ The vehicle speed is 32-104 km/h (20-65 mph).
^ When 3rd gear is commanded and within 2.5 seconds, the engine speed is 130 RPM less than the engine speed of the commanded 2nd gear.
CASE 3:
^ 3-4 shift commanded
^ The throttle position is 14-25% and is constant within 3%.
^ The vehicle speed is 56-128 km/h (35-80 mph).
^ When 4th gear is commanded and within 2.5 seconds, the engine speed is 5 RPM greater than the engine speed of the commanded 3rd gear.
CASE 4:
^ Fourth gear is commanded and the TCC is ON.
^ The throttle position is 7-32%.
^ The speed ratio is 37.5-39.5.
^ The TCC slip is 500-1000 RPM for more than 2.5 seconds.
CASE 5:
^ Fourth gear is commanded and the TCC is ON.
^ The throttle position is 7-32%.
^ The speed ratio is 26-28.
^ The TCC slip is -20 to +20 RPM for more than 2.5 seconds.
ACTION TAKEN WHEN THE DTC SETS
^ The PCM inhibits downshifts to 2nd gear if the vehicle speed is greater than 48 km/h (30 mph).
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) after two consecutive trips with a failure reported.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.
DIAGNOSTIC AIDS
^ Check for PRNDL DTC P0705. A PRNDL DTC affects transmission operation. A PRNDL DTC may set DTC P0751 falsely.
^ Inspect the transmission fluid for sediment.
^ Inspect the transmission filter for debris.
TEST DESCRIPTION
The number below refers to the step numbers on the diagnostic chart.
3. Once the DTC is verified, replace the 1-2 shift solenoid.