Diagnostic Instructions

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

P0777

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

Conditions for Clearing the DIC/DTC

DTCs P0776 and P0777 are Type A DTCs.

Diagnostic Aids

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

Special Tools

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.