Buick Regal: DTC P170A-P170E

Diagnostic Instructions

• Perform the Diagnostic System Check prior to using this diagnostic procedure: Refer to Diagnostic System Check - Vehicle
• Review the description of Strategy Based Diagnosis:Strategy Based Diagnosis
• An overview of each diagnostic category can be found here: Refer to Diagnostic Procedure Instructions

DTC Descriptor

DTC P170A

Transmission Hydraulic Circuit 2 Max Pressure Not Achieved

DTC P170B

Transmission Hydraulic Circuit 3 Max Pressure Not Achieved

DTC P170C

Transmission Hydraulic Circuit 4 Max Pressure Not Achieved

DTC P170D

Transmission Hydraulic Circuit 5 Max Pressure Not Achieved

DTC P170E

Transmission Hydraulic Circuit 6 Max Pressure Not Achieved

Circuit/System Description

The pressure control solenoid valves control fluid pressure to the C1, 2, 3, 4 and B1 clutches. The respective pressures were not reached when the transmission experienced an abnormal upshift/downshift or a tie-up during shifts.

Conditions for Running the DTC

• DTC P0563, P0601, P0602, P0604, P0711, P0712, P0713, P0717, P07BF, P07C0, P0722, P0748, P077C, P077D, P0778, P0798, P0962, P0963, P0966, P0967, P0970, P0971, P2716, P2720, P2721, P2725, P2729, P2730, P2734, P2738, P2739 = Not set
• Ignition=On
• Battery Voltage=9 to 32 V - For greater than 2 s
• Engine Speed=Greater than 400 RPM
• Transmission Range= Drive
• Transmission Fluid Temperature=Warmer than -20ºC (4ºF)
• Garage Shift =No
• Transmission OSS=Greater than 300 RPM
• Slip Detected=No
  • Accelerator Pedal=Greater than 70%
  • Engine Torque =Greater than 70 Nm (52 lb ft)
  • Transmission OSS=300 to 3000 RPM
  • Transmission OSS=Less than -50 RPM per second

Conditions for Setting the DTC

Condition 1

Clutch C1, C2, C3, C4, B1=Not released

Condition 2

Incorrect gear ratio@Current Gear - More than 5 times.

Actions Taken When the DTC Sets

DTCs listed in the DTC Descriptor Category=Type A DTC

Fail-Safe Mode=Active

Conditions for Clearing the DTC

DTCs listed in the DTC Descriptor Category=Type A DTC

Reference Information

Schematic: Reference

Refer to Automatic Transmission Controls Wiring Schematics

Connector End View: Reference

• Refer to Component Connector End View Index
• Refer to Inline Harness Connector End View Index

Component View: Reference

Refer to Disassembled Views.

Description and Operation

• Refer to Electronic Component Description Refer to Transmission General Description

Electrical Information: Reference

• Refer to Circuit Testing
• Refer to Connector Repairs
• Refer to Testing for Intermittent Conditions and Poor Connections
• Refer to Wiring Repairs

DTC Type: Reference

Refer to Powertrain Diagnostic Trouble Code (DTC) Type Definitions.

Scan Tool: Reference

Refer to Control Module: References.

Circuit/System Verification

1. Ignition - On / Vehicle - In Service Mode

2. Verify there are no DTCs set related to the following system/component:

• Q27A Pressure Control Solenoid Valve 1
• Q27B Pressure Control Solenoid Valve 2
• Q27C Pressure Control Solenoid Valve 3
• Q27D Pressure Control Solenoid Valve 4
• Q27E Pressure Control Solenoid Valve 5
• If other DTCs are set

Refer to: Diagnostic Trouble Code (DTC) List - Vehicle

• Go to next step: If no other DTCs are set

3. Verify the condition does not exist:Incorrect fluid level or condition. Refer to Transmission Fluid Level and Condition Check.

• If a condition exists

Repair or replace as necessary.

• Go to next step: If no condition exists

4. Verify there are no DTCs set related to the following system/component:K173 Transmission Range Control Module

• If any DTC is set

Refer to: Diagnostic Trouble Code (DTC) List - Vehicle

• Go to next step: If no DTC is set

5. Clear the DTCs.

6. Perform the configuration/reset function: Refer to Learned Values Reset.

7. Road test the vehicle. Refer to Road Test.

8. Verify DTC P170A, P170B, P170C, P170D, P170E is not set.

• {Test failed 1 time (s) }If any of the DTCs are set

1. Replace the component: Control Valve Body
2. Refer to:Step 5

• {Test failed 2 time (s) }If any of the DTCs are set

1. Replace the component: K71 Transmission Control Module
2. Refer to:Step 5

• {Test failed 3 time (s) }If any of the DTCs are set

1. Replace the component: T12 Automatic Transmission Assembly
2. Refer to:Step 5

• Go to next step: If none of the DTCs are set

9. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

10. Verify the DTC does not set.

• If the DTC sets

Refer to:Step 1

• Go to next step: If the DTC is not set

11. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair: Refer to Diagnostic Repair Verification

• Refer to Control Valve Body Replacement
• Refer to Transmission Replacement
• For control module replacement, programming, and setup: Refer to Control Module: References

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