Diagnostic Instructions
DTC Descriptors
DTC P0776: Clutch Pressure Control (PC) Solenoid 2 - Stuck Off
DTC P0777: Clutch Pressure Control (PC) Solenoid 2 - Stuck On
Circuit/System Description
The clutch pressure control (PC) solenoid 2 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The clutch PC solenoid 2 flows fluid to the 3-5-R clutch when commanded OFF and exhausts fluid when
commanded ON. The clutch PC solenoid 2 regulates the transmission fluid pressure to the 3-5-R clutch. The TCM calculates gear ratio based on data from the automatic transmission input speed sensor (ISS) and the output speed sensor (OSS).
The TCM compares the known transmission gear ratio to a calculated gear ratio for each commanded gear.
Conditions for Running the DTC
P0776
| - | The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F). |
| - | DTCs P0716, P0717, P0722, P0723, P1815, P1820, P1822, P1823, P1825, P1826 are not set. |
| - | The turbine speed is greater than or equal to 60 RPM, 3-5-R clutch is commanded ON |
| • | For 3rd gear steady state testing: |
| - | Active the ignition voltage. |
| - | The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F). |
| - | DTC P0716, P0717, P0722, P0723, P1915, P1825 are not set. |
| - | Active the high side driver. |
| - | The drive wheel speed is greater than or equal to 80 RPM. |
| - | The deviation of two wheel speeds at either side is less than or equal to 150 RPM. |
| - | The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds. |
| - | The transmission is in 3rd or 5th gear. |
| • | For 5th gear steady state testing: |
| - | Active the ignition voltage. |
| - | The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F). |
| - | DTCs P0716, P0717, P0722, P0723, P1915, P1825 are not set. |
| - | Active the high side driver. |
| - | The drive wheel speed is greater than or equal to 80 RPM. |
| - | The deviation of two wheel speeds at either side is less than or equal to 150 RPM. |
| - | The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds. |
| - | The transmission is in 3rd or 5th gear. |
P0777
| - | The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F). |
| - | DTCs P0716, P0717, P0722, P0723, P1815, P1820, P1822, P1823, P1825, P1826 are not set. |
| - | The transmission output shaft speed is greater than 200 RPM. |
| - | The turbine speed is greater than or equal to 200 RPM, 3-5-R clutch is commanded OFF. |
| • | For steady state testing: |
| - | Active the ignition voltage. |
| - | The Transmission Fluid Temperature (TFT) is greater than or equal to 0°C (32°F). |
| - | DTCs P0716, P0717, P0722, P0723, P1915, P1825 are not set. |
| - | Active the high side driver. |
| - | With the brake pedal not depressing or gear torque varies exceeds 250 N·m (184 lb ft) in 0.35 second. |
| - | The drive wheel speed is greater than or equal to 80 RPM. |
| - | The deviation of two wheel speeds at either side is less than or equal to 150 RPM. |
| - | The average deviation of the drive wheel and the driven wheel is less than 7 percent which could take up to 6 seconds. |
| - | The change of the transmission output shaft speed is greater than 1,300 RPM per second. |
| - | Commanded gear equals 1st, 2nd, 4th or 6th and has obtained a gear ratio. |
Conditions for Setting the DTC
P0776
Dynamic Test
| - | The transmission output shaft speed is greater than or equal to 60 RPM. |
| - | Commanded gear slip is equal to or greater than 100 RPM for 2.25 seconds. |
| - | The transmission output shaft speed is less than 60 RPM. |
| - | The turbine speed is greater than or equal to the calibrated value for 2.25 seconds. |
For 3rd gear steady state testing:
Fail Case 1
The command gear equals third, transmission case slip speed is 100 RPM or greater for 5 seconds.
Fail Case 2
Commanded gear accelerates to 4th and 4th gear box slip is less than or equal to 35 RPM or gear box slip is equal to or less than 100 RPM and PC Sol.3 commanded pressure is at maximum for 4 seconds.
The 5th gear steady state testing:
Fail Case 1 and Fail Case 2 must occur in sequential order.
Fail Case 1
The command gear equals third, transmission case slip speed is 100 RPM or greater for 5 seconds.
Fail Case 2
Commanded gear accelerates to 4th and 4th gear box slip is less than or equal to 35 RPM or gear box slip is equal to or less than 100 RPM and PC Sol.3 commanded pressure is at maximum for 4 seconds.
P0777
Dynamic Test
| • | As PC Sol. 2 of 3-5-R clutch commanded pressure is 0 kPa for calibrated amount of time. |
| • | The obtained gear box slip is equal to or less than 40 RPM for a calibrated amount of time. |
Steady State Test:
Fail Case 1 and Fail Case 2 must occur in sequential order, and the transmision is ont at 3rd or 5th gear.
Fail Case 1
| • | The transmission OSS speed drops less than or equal to a calibrated value. |
| • | The above conditions exist for up to 0.3 seconds. |
Fail Case 2
The clutch is off-going and the difference of the gear speed is between 35-100 RPM for 4 seconds.
Action Taken When the DTC Sets
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DIC/DTC
DTCs P0776 and P0777 are Type A DTCs.
Diagnostic Aids
When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
DTC Type Reference
Electrical Information Reference
Scan Tool Reference
Special Tools
Circuit/System Verification
- Perform the
Transmission Fluid Check.
- Operate the vehicle in drive with the calculated throttle position greater than 15 percent to obtain 72 km/h (45 mph).
| ⇒ | If the DTC resets, go to Circuit/System Testing. |
Circuit/System Testing
- Perform the
Line Pressure Check.
| ⇒ | If the pressure is out of specification, correct this concern first. |
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly Cleaning and retest the DTC as outlined in the Circuit/System Verification steps.
| ⇒ | If the DTC resets, continue on with testing. |
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly Inspection.
| ⇒ | If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly. |
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test.
| ⇒ | If the solenoid is found to be leaking or stuck closed, replace the control solenoid (w/body and TCM) valve assembly. |
- Inspect the control valve upper body assembly for sticking valves, damage, scored bores, or debris.
| ⇒ | If a concern if found in the valve body, repair or replace the valve body as necessary. |
- Inspect the 3-5-R clutch assembly for damage.
| ⇒ | If a concern is found in the 3-5-R clutch assembly, repair or replace as necessary. |
Component Testing
PC Sol 2 Operation
Operating Conditions
| Normal Operation
| Stuck OFF
| Stuck ON
|
Steady State Gears 3, 5
| 3, 5
| Neutral
| 3, 5
|
Steady State Gears 1, 2, 4, 6
| 1, 2, 4, 6
| 1, 2, 4, 6
| 3, 5
|
Garage Shift
| Park/Neutral to Reverse/Drive
| Neutral
| 1 Gear
|
Downshift from gears 4, 5, 6 to 3, 5
| 3, 5
| Neutral
| 3, 5
|
Upshift from gears 3, 5 to 4, 5, 6
| 4, 5, 6
| 4, 5, 6
| 3, 5
|
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
