• | 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. |
The following fault table will help determine if a hydraulic circuit or an incorrect position of a valve train component affects 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 |
| 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 |
| P0776 P0777 | ||||||||||||||
Upper Control Valve Body | The B-2-6 regulator valve stuck - debris, sediment, binding or scored bore | P0777 |
Gear | 1-2-3-4 CL PC SOL 5 | 2-6 CL PC SOL 4 | 3-5 REV CL PC SOL 2 | LOW REV 4-5-6 CL PC SOL 3 |
---|---|---|---|---|
Park | OFF | OFF | OFF | ON |
Reverse | OFF | OFF | ON | ON |
Neutral | OFF | OFF | OFF | ON |
1st Braking | ON | OFF | OFF | ON |
1st | ON | OFF | OFF | OFF |
2nd | ON | ON | OFF | OFF |
3rd | ON | OFF | ON | OFF |
4th | ON | OFF | OFF | ON |
5th | OFF | OFF | ON | ON |
6th | OFF | ON | OFF | ON |
The clutch pressure control (PC) solenoid 2 is integral to the control solenoid (w/body and TCM) valve assembly and 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. 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 reset.
• | No DTCs P0716 or P0717 are active or have failed this key on. |
• | No DTCs P0722 or P0723 are active or have failed this key on. |
• | No DTC P1825 is active or has failed this key on. |
• | Ignition voltage is between 8.6-18.0 volts. |
• | Transmission fluid temperature (TFT) is equal to or greater than 0°C (32°F). |
• | TCM high side driver (HSD) 1 is enabled. |
• | Average driven wheel speed is 80 RPM or more. |
• | Side to side average wheel speed between driven and non-driven wheel is 150 RPM or less for 6 seconds. |
• | The transmission input shaft speed is greater than 60 RPM. |
• | PC solenoid 2 is commanded On. |
• | 3rd (1.532:1) or 5th (0.852:1) gear ratio has been achieved. |
• | No DTCs P0716 or P0717 are active or have failed this key on. |
• | No DTCs P0722 or P0723 are active or have failed this key on. |
• | No DTC P1825 is active or has failed this key on. |
• | TFT is equal to or greater than 0°C (32°F). |
• | The transmission input and output shaft speed is greater than 200 RPM. |
• | PC solenoid 2 is commanded Off. |
The TCM detects an incorrect on-coming clutch gear ratio, or flare, when the 3-5-R clutch is commanded On for 2.25 seconds and the transmission input shaft speed is greater than 60 to 100 RPM from the anticipated input shaft speed.
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 greater than 40 RPM from the anticipated input shaft speed.
• | DTCs P0776 and P0777 are Type A DTCs. |
• | The TCM commands maximum line pressure. |
• | The TCM inhibits TCC. |
• | The TCM freezes transmission adaptive functions. |
DTCs P0776 and P0777 are Type A DTCs.
• | When attempting to set transmission performance DTCs, observe the Freeze Frame and Failure Records to assist in duplicating the failure conditions. |
• | If diagnosing a P0776 DTC 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. |
Transmission Component and System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
DT-47825 Control Solenoid Test Plate
⇒ | If the DTC resets, go to Circuit/System Testing. |
⇒ | If the pressure is out of specification, correct this concern first. |
⇒ | If the DTC resets, continue with testing. |
⇒ | If a concern is found, repair or replace the control solenoid (w/body and TCM) valve assembly. |
⇒ | If the solenoid is found to be leaking or stuck closed, replace the control solenoid (w/body and TCM) valve assembly. |
⇒ | If a concern if found in the valve body, repair or replace the valve body as necessary. |
⇒ | If a concern is found in the 3-5-R clutch assembly, repair or replace as necessary. |
Operating the transmission in the following condition will verify the PC solenoid or a portion of the hydraulic control circuit is not functioning as it should.
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 |
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 |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control valve body replacement. Refer to Control Valve Lower Body and Upper Body Replacement . |
• | 3-5-R clutch assembly repair or replace. Refer to 1-2-3-4 and 3-5 Reverse Clutch Overhaul . |
• | Control solenoid (w/body and TCM) valve assembly replacement. Refer to Control Module References for replacement, setup, and programming. |
• | Perform the Service Fast Learn Adapts if internal transmission repairs are performed. |