P0776
DTC P0776 or P0777
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
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 valve assembly, which has no serviceable components. The PC solenoid 2 regulates transmission fluid pressure to the 3-5-Reverse clutch regulator valve which controls pressure to the 3-5-Reverse 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.
* Ignition voltage is 8.6 volts or greater.
* Engine speed is 400 RPM or greater for 5.0 seconds.
* Transmission fluid temperature (TFT) is 0°C (32°F) or greater.
* Transmission output speed is 16 RPM or greater, or the throttle position is 0.4 percent or greater.
* Throttle position signal is valid.
* High side driver 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.
* Ignition voltage is 8.6 volts or greater.
* Engine speed is 400 RPM or greater for 5.0 seconds.
* TFT is 0°C (32°F) or greater.
* Engine torque is 20 Nm (15 lb ft) or greater.
* Transmission output speed is 16 RPM or greater, or the throttle position is 0.4 percent or greater.
* Throttle position signal is valid.
* High side driver is enabled.
Conditions for Setting the DTC
P0776
TCM has detected an incorrect gear ratio or neutral condition when the 3-5-Reverse clutch is commanded ON. This condition must occur 3 times.
P0777
TCM has detected an incorrect gear ratio change when the 3-5-Reverse clutch is commanded OFF during a shift or when 3rd ratio is detected in 1st gear. This condition must occur 3 times.
Action Taken When the DTC Sets
P0776
* DTC P0776 is a Type A DTC.
* TCM commands maximum line pressure.
* TCM inhibits Tap Up/Down function.
* TCM freezes transmission adaptive functions.
* TCM inhibits manual shifting of forward gears.
* TCM limits the transmission to Reverse, 2nd, and 4th gear operation.
P0777
* DTC P0777 is a Type A DTC.
* TCM commands maximum line pressure.
* TCM inhibits Tap Up/Down function.
* TCM inhibits manual shifting of forward gears.
* TCM freezes transmission adaptive functions.
* TCM limits the transmission to 3rd gear and Reverse operation.
* TCM inhibits neutral idle.
Conditions for Clearing the DIC/DTC
DTCs P0776 and P0777 are Type A DTCs.
Diagnostic Aids
Before performing a road test, configure and setup the scan tool for snapshot mode. This will allow you to display, monitor, and verify multiple transmission data parameters at one time, after the road test.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics Electrical Diagrams
Connector End View Reference
* Component Connector End Views A/C Compressor Clutch
* Inline Harness Connector End Views X101
Description and Operation
Transmission General Description Transmission General Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References
Circuit/System Verification
Warning:
Refer to Parking Brake and Drive Wheels Warning Parking Brake and Drive Wheels Warning in the preface section.
Note:
If other DTCs are set, diagnose those DTCs first.
1. Engine idling in Park, with parking brake applied and drive wheels chocked.
2. Verify correct transmission fluid level and condition. Refer to Transmission Fluid Level and Condition Check Testing and Inspection.
3. Verify with a scan tool the TFP Switch 1 parameter values are correct for the Park, Reverse, and Neutral gear select lever positions. Refer to Transmission Fluid Pressure Switch Logic Transmission Fluid Pressure Switch Logic.
• If not the correct values for TFP Switch 1
Refer to Circuit/System Testing below.
• If TFP Switch 1 values are correct
4. Gear select lever in Drive range. Verify the TFP Switch 1 parameter states are correct for all forward ranges when commanded with a scan tool. Refer to Transmission Fluid Pressure Switch Logic Transmission Fluid Pressure Switch Logic
• If not the correct values for TFP Switch 1
Refer to Circuit/System Testing below.
• If TFP Switch 1 values are correct
5. Ignition ON, clear the TCM DTCs.
6. Perform the Road Test Initial Inspection and Diagnostic Overview. Verify the transmission operation performs as indicated in the road test instructions and DTC P0776 or P0777 did not set.
• If DTC P0776 or P0777 sets
Refer to Circuit/System Testing below.
• If DTC P0776 or P0777 did not set
7. 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 Testing for Intermittent Conditions and Poor Connections.
Circuit/System Testing
Note:
You must perform the Circuit/System Verification first.
1. Verify the transmission line pressures are within the ranges specified in the Line PC Solenoid Valve Pressure table. Refer to Line Pressure Check Line Pressure Check and Solenoid Valve Pressure Solenoid Valve Pressure.
• If line pressures are not within the specified ranges
Refer to Fluid Pressure High or Low Fluid Pressure High or Low
• If line pressures are within the specified ranges
2. Ignition OFF, remove the Q8 control solenoid valve assembly. Refer to Control Solenoid Valve and Transmission Control Module Assembly Replacement Service and Repair.
3. Perform the Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test. A pressure change should occur for each solenoid valve.
• If a pressure change does not occur for each solenoid
Replace the Q8 control solenoid valve assembly
• If a pressure change occurs for each solenoid
4. Listed in the table below, are conditions for each component that could set DTC P0776 or P0777. Carefully inspect each component for that condition. Repair or replace as necessary.
Repair Instructions
Note:
* Perform the Reset Transmission Adapts Reset Transmission Adapts following all transmission related repairs.
* Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection Control Solenoid Valve and Transmission Control Module Assembly Inspection.
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Control Valve Lower Body and Upper Body Replacement Control Valve Lower Body and Upper Body Replacement
* Low and Reverse Clutch and 1-2-3-4 Clutch Plate Removal Low and Reverse Clutch and 1-2-3-4 Clutch Plate Removal
* Control Module References Control Module References for control solenoid valve assembly replacement, setup, and programming