For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | 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

### Diagnostic Fault Information

The following fault table gives examples of how hydraulic circuit problems and malfunctioning hard parts affect the transmission operation.

Component | Cause | DTCs
--- | --- | ---
1-2-3-4 and 3-5-R Clutch Housing Assembly | 1-2-3-4 clutch backing plate retaining ring not seated, causing the piston to over-travel and cut 1-2-3-4 clutch piston seal | P0776 P0777
4-5-6 Clutch Housing | 4-5-6 Housing broken hub weld | P0776
Control Solenoid (w/body and TCM) Valve Assembly |

• | Clutch pressure control solenoid 2:

- | Always exhausting (Stuck On)

- | Not exhausting (Stuck Off)

- | Needle piston or armature pin binding

- | Control signal fluid supply leak - valve body filter plate assembly cracked or damaged gasket seal

- | O-ring seals leaking

• | Valve body filter plate assembly cracked, blocked or damaged gasket seal

P0776

P0777

Fluid Pump Cover Assembly | Fluid Pump Cover Vanes and Fluid Pump Rotor broken - wrong pump rotor installed | P0776
Fluid Pump Cover Assembly | Isolator valve sticking or stuck - debris, sediment, binding or scored bore | P0776 P0777
Upper Control Valve Body | 3-5-R regulator valve stuck - debris, sediment, binding or scored bore. | P0776
Upper Control Valve Body |

• | Actuator feed limit circuit supply fluid to solenoid restricted or not available (debris or sediment blockage)

• | B-R-1 and 4-5-6 clutch regulator valve not in the applied position - debris, sediment, binding or scored

• | 4-5-6 clutch boost valve not exhausting - binding or scored bore

P0776

P0777

Upper Control Valve Body | The B-2-6 regulator valve stuck - debris, sediment, binding or scored bore | P0777

#### Shift Solenoid Valve State and Gear Ratio

Gear | Shift SOL 1 | 1-2-3-4 CL PC SOL 5 N.L. | 2-6 CL PC SOL 4 N.L. | 3-5 REV CL PC SOL 2 N.H. | LOW REV 4-5-6 CL PC SOL 3 N.H. | Gear Ratio
--- | --- | --- | --- | --- | --- | ---
Park | ON | OFF | OFF | OFF | ON | --
Reverse | ON | OFF | OFF | ON | ON | 2.940
Neutral | ON | OFF | OFF | OFF | ON | --
1st Braking | ON | ON | OFF | OFF | ON | 4.584
1st | OFF | ON | OFF | OFF | OFF | 4.584
2nd | OFF | ON | ON | OFF | OFF | 2.964
3rd | OFF | ON | OFF | ON | OFF | 1.912
4th | OFF | ON | OFF | OFF | ON | 1.446
5th | OFF | OFF | OFF | ON | ON | 1.000
6th | OFF | OFF | ON | OFF | ON | 0.746
Effective Final Drive Ratio - 6T40/45 - 3.17/3.87 For shift solenoid 1, "ON" = Solenoid Energized (Pressurized) "OFF" = Solenoid De-energized (No Pressure) For pressure control solenoids, "ON" = Pressurized, "OFF" = No Pressure

### Circuit/System Description

The clutch pressure control (PC) solenoid 2 is part of the control solenoid (w/body and TCM) valve assembly. The control solenoid (w/body and TCM) valve assembly has no serviceable parts. The PC solenoid 2 is a normally high-pressure control solenoid which provides fluid pressure to the 3-5-R clutch regulator valve which regulates the transmission fluid pressure to the 3-5-R clutch. The TCM controls the solenoid pressure by regulating the exhaust fluid. When the TCM commands the solenoid off, the exhausting fluid is stopped and the 3-5-R pressure is high. When commanded on, the clutch PC solenoid 2 regulates the amount of exhausting transmission fluid. Solenoid power is supplied by the TCM through a high side driver (HSD). The HSD protects the circuits and components that the TCM powers. Should the circuit overload the driver will shutdown. After the overload is removed the HSD resets. 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

• | No ISS DTCs P0716 or P0717.

• | No OSS DTCs P0722 or P0723.

• | No IMS DTCs P1825 or P1915.

• | The ignition voltage is between 9.0 volts and 19.0 volts.

• | The transmission fluid temperature is 0°C (32°F) or greater.

• | The transmission input speed is 60 RPM or greater.

• | The 3-5-R clutch is commanded ON.

• | The HSD is enabled.

#### P0777

• | No ISS DTCs P0716 or P0717.

• | No OSS DTCs P0722 or P0723.

• | No IMS DTCs P1825 or P1915.

• | The ignition voltage is between 9.0 volts and 19.0 volts.

• | The transmission fluid temperature is 0°C (32°F) or greater.

• | The transmission output shaft speed is 200 RPM or greater.

• | 3-5-R clutch is commanded OFF.

• | The HSD is enabled.

### 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 4.0 seconds and the transmission input shaft speed is 33 RPM or greater from the anticipated input shaft speed.

#### P0777

The TCM detects an incorrect off-going clutch gear ratio, or tie-up, when the 3-5-R clutch is commanded OFF for 1.2 seconds and the transmission input shaft speed is 40 RPM or less from the anticipated input shaft speed.

### Action Taken When the DTC Sets

• | DTCs P0776 and P0777 are Type A DTCs.

• | The TCM commands maximum line pressure.

• | The TCM inhibits TCC.

• | The TCM freezes transmission adaptive functions.

• | The TCM inhibits TAP Up/TAP Down.

### Conditions for Clearing the DIC/DTC

DTCs P0776 and P0777 are Type A DTCs.

### Diagnostic Aids

• | DTC P0776 detects neutral when 3rd or 5th gear is commanded.

• | DTC P0777 detects a tie-up condition when shifting from 3rd or 5th.

• | When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions.

• | If diagnosing DTC P0776 and you know the 3-5-R Clutch is not stuck On, inspect for a sticking clutch select valve 2.

• | If by shifting to reverse you obtain a neutral state, PC Sol. 2 could be stuck off. Perform a Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test to verify the solenoid is stuck off.

• | If by shifting to neutral you obtain a reverse state, PC Sol. 2 could be stuck on. Perform a Control Solenoid Valve and Transmission Control Module Assembly Solenoid Performance Test to verify the solenoid is stuck on.

• | Use the scan tool to view the TFP Switch status and refer to the Transmission Fluid Pressure Switch Logic table to determine when a TFP switch should be active or inactive for a given gear. This will help to determine if the hydraulic circuit functioning and if the PC solenoid or the valve train is in an incorrect position.

### Reference Information

#### Schematic Reference

• | Drive Range, Third Gear

• | Drive Range, Fifth Gear

#### Description and Operation

• | Transmission General Description

• | Transmission Component and System Description

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

#### Special Tools

• | DT-48616 Control Solenoid Test Plate

• | DT-48616-10 Adapter Harness

### Circuit/System Verification

1. Perform the Transmission Fluid Check .
2. 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

Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Perform the Line Pressure Check .

⇒ | If the pressure is out of specification, correct this concern first.

2. 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.

3. 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.

4. 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.

5. Inspect the control valve lower 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.

6. 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

Operating the transmission under the following conditions will verify that the PC solenoid or a portion of the hydraulic control circuit is not functioning as it should.

#### P0776: Clutch Pressure Control (PC) Solenoid 2 - Stuck Off

Transmission Operating Conditions | Transmission Condition if PC Sol. 2 is Stuck Off
--- | ---
Steady State: Gears 3rd or 5th | Neutral
Garage Shift: Park/Neutral to Reverse/Drive | Neutral
Downshift: from gears 6th, 5th, 4th to 5th or 3rd | Neutral

#### P0777: Clutch Pressure Control (PC) Solenoid 2 - Stuck On

Transmission Operating Conditions | Transmission Condition if PC Sol. 2 is Stuck On
--- | ---
Steady State: Gears 1st, 2nd, 4th, or 6th | 3rd or 5th
Garage Shift: Park/Neutral to Reverse/Drive | 1st (Engine Braking)
Downshift: from gears 4th, 5th, 6th to 3rd or 5th | 3rd or 5th
Upshift: from gears 3rd, 5th to 4th, 5th, or 6th | 3rd or 5th

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

| Important: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection .

• | Refer to Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming.

• | Perform the Service Fast Learn Adapts following all transmission related repairs.

• | Perform the:

- | Internal Components Removal

- | 3-5-Reverse and 4-5-6 Clutch Housing Disassemble

- | 3-5-Reverse and 4-5-6 Clutch Housing Assemble

- | 3-5-Reverse and 4-5-6 Clutch Housing, and Input, Reaction, and Output Carrier Installation