DTC P0776 or P0777
Diagnostic Instructions
DTC Descriptors
DTC P0776: Pressure Control Solenoid Valve 2
Stuck Off
DTC P0777: Pressure Control Solenoid
Valve 2 Stuck On
Circuit/System Description
The clutch pressure control (PC) solenoid 2 is part of
the control solenoid valve assembly which has no serviceable
components. PC solenoid 2 regulates transmission fluid
pressure to the 3-5-R regulator valve which controls pressure to
the 3-5-R clutch. The transmission control module (TCM)
calculates gear ratio based on the RPM signals from the input speed
sensor (ISS) and the output speed sensor (OSS). The TCM
compares the expected transmission gear ratio to the calculated
gear ratio for each commanded gear.
Conditions for Running the DTC
P0776
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or
P182E is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The transmission fluid temperature (TFT) is
-7°C (19°F) or greater. |
• |
The transmission output speed is 650 RPM or
greater or the throttle position is 0.5 percent or
greater. |
• |
The throttle position signal is valid. |
• |
The high side driver (HSD) is enabled. |
P0777
• |
DTC P0101, P0102, P0103, P0106, P0107, P0108,
P0171, P0172, P0174, P0175, P0201, P0202, P0203, P0204, P0205,
P0206, P0207, P0208, P0300, P0301, P0302, P0303, P0304, P0305,
P0306, P0307, P0308, P0401, P042E, P0716, P0717, P0722, P0723, or
P182E is not set. |
• |
The engine speed is greater than 400 RPM for
5 seconds. |
• |
The ignition voltage is 9.0 volts or
greater. |
• |
The TFT is -7°C (19°F) or greater. |
• |
The transmission output shaft speed is
200 RPM or greater. |
• |
The throttle position signal is valid. |
Conditions for Setting the DTC
P0776
The TCM detects an incorrect on-coming clutch gear ratio, or
flare, when the 3-5-R clutch is commanded ON for 3 seconds and
the transmission input shaft speed is 400 RPM or greater from
the anticipated input shaft speed. This must occur
3 times.
P0777
The TCM detects an incorrect off-going clutch gear ratio, or
tie-up, when the 3-5-R clutch is commanded OFF for 1 second
and the transmission input shaft speed is 400 RPM or less from
the anticipated input shaft speed. This must occur
3 times.
Action Taken When the DTC Sets
P0776
• |
DTC P0776 is a Type A DTC. |
• |
The TCM commands maximum line pressure. |
• |
The TCM limits the transmission to reverse and 2nd
gear. |
• |
The TCM freezes transmission adaptive
functions. |
• |
The TCM inhibits TAP Up/TAP Down function. |
• |
The TCM inhibits manual shifting of forward
gears. |
P0777
• |
DTC P0777 is a Type A DTC. |
• |
The TCM commands maximum line pressure. |
• |
The TCM limits the transmission to reverse and 3rd
gear. |
• |
The TCM freezes transmission adaptive
functions. |
• |
The TCM inhibits TAP Up/TAP Down function. |
• |
The TCM inhibits manual shifting of forward
gears. |
Conditions for Clearing the DIC/DTC
DTCs P0776 and P0777 are Type A DTCs.
Reference Information
Schematic Reference
Description and Operation
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Warning: Apply the handbrake and
chock the drive wheels before performing this procedure in order to
prevent bodily injury.
Note: If other DTCs are set,
diagnose those DTCs first.
- Engine ticking over in Park, with handbrake applied
and drive wheels chocked.
- Perform the
Transmission Fluid Level and Condition Check , to verify
correct fluid level and condition.
- Monitor the Transmission Fluid Pressure Switch 1
parameter with a scan tool. Place the gear select lever in Park,
Reverse, and Neutral range. Verify the Transmission Fluid Pressure
Switch 1 parameter states are correct for Park, Reverse, and
Neutral. Refer to
Transmission Fluid Pressure Switch Logic .
- Place the gear select lever in Drive range. Command
the shift transmission with a scan tool through all forward ranges.
Verify the Transmission Fluid Pressure Switch 1 parameter
states are correct for all forward ranges. Refer to
Transmission Fluid Pressure Switch Logic .
- Engine ticking over in Park, verify with a scan tool
the Transmission ISS/OSS Supply Voltage test status parameter
displays OK.
- Engine ticking over in Park. Observe the Transmission
ISS parameter on the scan tool, while varying the engine speed. The
Transmission ISS parameter should vary with engine speed and not
drop out.
- Operate the vehicle at 16-32 km/h
(10-20 mph) while observing the Transmission OSS parameter on
the scan tool. The Transmission OSS parameter should vary with the
vehicle speed and not drop out.
Note: Perform a scan tool
snapshot during the road test.
- Perform the
Road Test . Verify the transmission operation performs as
indicated in the road test instructions.
- Review the scan tool snapshot data. Verify the
following transmission data parameters display the correct values
for each gear range.
• |
Pressure Control Solenoid Valve 2 Pressure
Command |
• |
Transmission Fluid Pressure Switch 1 |
- After performing the above steps, verify that the DTC
does not reset by operating the vehicle within the Conditions for
Running the DTC. You may also operate the vehicle within the
conditions you observe from the Freeze Frame/Failure Records data.
If the vehicle passes the Circuit/System Verification procedure,
then STOP. Do not perform the Circuit/System Testing or Component
Testing as this may result in an unnecessary part replacement.
Refer to
Testing for Intermittent Conditions and Poor Connections .
Circuit/System Testing
Note: You must perform the
Circuit/System Verification first.
- Perform the
Line Pressure Check . Verify the transmission line pressures
are within the range specified in the Line PC Solenoid Valve
Pressure table. Refer to
Solenoid Valve Pressure .
- Ignition OFF, remove the Q8 control solenoid valve
assembly. Refer to
Control Solenoid Valve and Transmission Control Module Assembly
Replacement .
- Perform the
Control Solenoid Valve and Transmission Control Module Assembly
Solenoid Performance Test .
⇒ |
If the Q8 control solenoid valve assembly does not
pass the performance test, replace the Q8 control solenoid valve
assembly. |
- Inspect for the following conditions and repair or
replace as necessary.
DTCs
|
Component
|
Condition
|
P0776
P0777
|
Control Valve Body Assembly
|
3-5-R Regulator Valve stuck/sticking - debris, binding, damaged
valve, or scored bore
|
P0776
P0777
|
Q8 Control Solenoid Valve Assembly
|
• |
Clutch Pressure Control Solenoid 2 |
• |
Valve body filter plate assembly cracked, blocked,
or damaged gasket seal |
|
P0776
P0777
|
Control Valve Body Assembly
|
• |
Actuator feed limit circuit supply fluid to
solenoids restricted or not available - debris or sediment
blockage |
• |
3-5-R clutch regulator valve not in the applied
position - debris, binding, damaged valve, or scored bore |
• |
Control valve body ball check valve not seating
correctly - debris |
|
P0776
P0777
|
Torque Converter (w/Fluid Pump) Housing Assembly
|
Fluid pump housing/gear damaged/scored
|
P0776
|
3-5-R and 4-5-6 Clutch Housing Assembly
|
3-5-R clutch backing plate retaining ring not seated, causing
clutch pack over-travel
|
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|