DTC P0751 1-2 Shift Solenoid Valve
Performance - No First or Fourth Gear 3.8L
The 1-2 shift solenoid (SS) valve controls the fluid flow acting on the
1-2 and 3-4 shift valves. The 1-2 SS valve is a normally-open exhaust valve
that is used with the 2-3 SS valve, in order to allow four different shifting
combinations.
When the PCM detects a
2-2-3-3 shift pattern, then DTC P0751 sets. DTC P0751 is a type B
DTC.
Conditions
for Running the DTC
- No TP sensor DTCs P0122 or P0123.
- 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.
- No transmission component slipping
DTC P1870.
- The engine speed is greater than
450 RPM for 5 seconds.
- The engine is not in fuel cutoff.
- The gear range is D4, D3, D2 or D1.
- The TP angle is greater than 9
percent.
- The transmission fluid temperature
is 20-130°C (68-266°F).
- The system voltage is
8-18 volts.
- The engine torque is
50-400 lbs ft.
- The transmission output speed is
greater than 150 RPM.
Conditions
for Setting the DTC
DTC P0751 sets if
both of the following conditions occur twice:
Condition 1
- The PCM commands first gear for
2 seconds.
- The engine speed is greater than
2.95 times the TCC slip speed.
- The estimated gear ratio is 1.2 to
1.825.
- All conditions are met for
0.5 second.
Condition 2
- The PCM commands fourth gear for
1 second.
- The engine speed is greater than
2.44 times the TCC slip speed.
- The estimated gear ratio is 0.95 to
1.15.
- All conditions are met for
6 seconds.
Action
Taken When the DTC Sets
- The PCM illuminates the malfunction
indicator lamp (MIL).
- The PCM commands D2 line pressure.
- The PCM freezes shift adapts from
being updated.
- 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.
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 fault no longer exists and/or the ignition switch is OFF
long enough in order to power down the PCM.
- Verify that the transmission meets
the specifications in the Shift
Speed table.
- Other internal transmission failures
may cause more than one shift to occur.
- Refer to the Shift
Solenoid Valve State and Gear Ratio table.
The numbers below refer
to the step numbers on the diagnostic table.
|
DTC P0751 1-2 SS Valve Performance - No First or Fourth
Gear (3.8L) Step |
Action |
Value(s) |
Yes |
No |
|
Did
you perform the Powertrain Diagnostic System Check?
|
-- |
Go to A
Powertrain On Board Diagnostic (OBD) System Check
in Engine Controls |
||
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.
Did
you detect a 2-2-3-3 shift pattern? |
-- |
Go to Diagnostic Aids |
||
|
Check
the shift solenoid/hydraulic circuit for the following conditions:
Did
you find and correct the condition? |
-- |
-- |
||
|
Perform
the following procedure in order to verify the repair:
Has
the test run and passed? |
-- |
System OK |