DTC P0751 2.2L
Circuit Description
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 1-1-4-4 or a 2-2-3-3 shift pattern, depending
on the state of the mechanical failure, then DTC P0751 sets. DTC P0751
is a type A 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. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The vehicle speed is greater than 8 km/h (5 mph). |
| • | The TP angle is 10-50 percent. |
| • | The TP angle is constant within 6 percent. |
| • | The transmission fluid temperature is 20-130°C (68-266°F). |
| • | The PCM commands a 1-2, 2-3 and 3-4 shift. |
| • | The TCC is commanded ON. |
Conditions for Setting the DTC
DTC P0751 sets if the following conditions occur three times:
| • | Within 2 seconds, the engine speed in 2nd gear is 80 RPM
greater than the last speed in 1st gear. |
| • | Within 2 seconds, the engine speed in 3rd gear is 100 RPM
less than the last speed in 2nd gear. |
| • | Within 2.5 seconds, the engine speed in 4th gear is 10 RPM
greater than the last speed in 3rd gear. |
All of the above conditions are met and one of the following conditions
occurs:
Condition 1
| • | The speed ratio is 0.95 to 1.25, speed ratio is engine speed divided
by transmission output speed. |
| • | The TCC slip speed is 400-1,200 RPM for 4 seconds. |
Condition 2
| • | The speed ratio is 0.65 to 0.8. |
| • | The TCC slip speed is -20 to +50 RPM for greater
than 4 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM commands D2 line pressure. |
| • | The PCM inhibits 3-2 downshifts if the vehicle speed is greater
than 48 km/h (30 mph). |
| • | 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 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 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. |
| • | Other internal transmission failures may cause more than one shift
to occur. |
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 P0751 (2.2L)
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 - 2.2L
|
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 1-1-4-4 or 2-2-3-3 shift pattern?
| --
| Go to
Step 3
| Go to
Intermittent Conditions
in Engine Controls - 2.2L
|
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 20% and accelerate to 88 km/h (55 mph). |
| • | If the throttle moves more than 6%, stop the vehicle and start
over. |
- Select Specific DTC.
- Enter DTC P0751.
Has the test run and passed?
| --
| Go to
Step 5
| Go to
Step 2
|
5
| 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?
| --
| Go to
Diagnostic Trouble Code (DTC) List
in Engine Controls - 2.2L
| System OK
|
DTC P0751 4.3L
Circuit Description
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. |
| • | 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 engine torque is 68-542 N·m (50-400 lb ft). |
| • | The transmission output speed is 150 RPM or greater. |
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 estimated gear ratio is 1.2-1.825. |
| • | All conditions are met for 0.5 seconds. |
Condition 2
| • | The PCM commands fourth gear for 1 second. |
| • | The estimated gear ratio is 0.95-1.15. |
| • | 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 inhibits 3-2 downshift if the vehicle speed is 48 km/h
(30 mph) or greater. |
| • | 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. |
Diagnostic Aids
| • | Verify that the transmission meets the specifications in the
Shift Speed
table. |
| • | Other internal transmission failures may cause more than one shift
to occur. |
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 P0751 (4.3L)
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 - 4.3L
|
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 2-2-3-3 shift pattern?
| --
| Go to
Step 3
| Go to
Intermittent Conditions
in Engine Controls - 4.3L
|
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 20% and accelerate to 88 km/h (55 mph).
- Select Specific DTC.
- Enter DTC P0751.
Has the test run and passed?
| --
| Go to
Step 5
| Go to
Step 2
|
5
| 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?
| --
| Go to
Diagnostic Trouble Code (DTC) List
in Engine Controls - 4.3L
| System OK
|
