Buick Regal: DTC P0722, P077C, or P077D

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 P0722

Output Speed Sensor Circuit No Signal

DTC P077C

Output Speed Sensor Circuit Low Voltage

DTC P077D

Output Speed Sensor Circuit High Voltage

Diagnostic Fault Information

Typical Scan Tool Data

Transmission OSS

Circuit/System Description

The sensor is an input to the control module K71. The input signal is used to determine the rotational speed of the component:Output Shaft The control module uses this data, along with other data, to adjust or control the following:

• Torque Converter Clutch
• Transmission Shifting

Conditions for Running the DTC

P0722

• DTC P077C, P077D, P07BF, P07C0, P0973, P0974, P0748, P0778, P0798, P0962, P0963, P0967, P0970.

  P0971, P2716, P2720, P2721, P2725, P2729, P2730, P2734, P2738, P2739 = Not set

• Engine Speed= Greater than 400 RPM
• Fail-Safe Mode=Inactive
• Ignition Voltage=10.2 to 15.5 V
• K71 Transmission Control Module= Communication Enabled
• Transmission Range=Drive

Frequency the DTC runs=Continuously - After the running conditions are met - For 2 s

P077C, P077D

• Engine Speed= Greater than 400 RPM
• Ignition Voltage=10.2 to 15.5 V
• K71 Transmission Control Module= Communication Enabled

Frequency the DTC runs=Continuously - After the running conditions are met - For 2 s

Conditions for Setting the DTC

P0722

Transmission OSS=0 RPM & Transmission ISS=Greater than 0 RPM

P077C

Transmission OSS=Invalid Signal Received - Short to Ground

P077D

Transmission OSS=Invalid Signal Received - Short to Voltage

Actions Taken When the DTC Sets

DTCs listed in the DTC Descriptor Category=Type A DTC

• Autostart/Autostop=Disabled - If equipped
• Fail-Safe Mode=Active
• { P077C, P077D }Transmission gear allowed=4th Gear - After a stop
• { P0722 }Transmission gear allowed=6th gear
• Transmission ISS=Calculated

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

Component View: Reference

Refer to Disassembled Views

Description and Operation

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. Engine - Running.

2. Transmission - Park.

CAUTION: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel.

3. Raise and support the vehicle.

4. Transmission - Drive.

5. Verify the scan tool parameter:Transmission OSS=The value should change smoothly and gradually as the vehicle speed is increased and decreased.

• If the value does not change smoothly and gradually

Refer to Circuit/System Testing

• Go to next step: If the value does not change smoothly and gradually

6. 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.

Verify the DTC does not set.

• If the DTC sets

Refer to Circuit/System Testing

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

7. All OK.

Circuit/System Testing

NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

1. Ignition/Vehicle & All vehicle systems - Off.

2. Remove the component:K71 Transmission Control Module.

NOTE: Twisting or tilting of the transmission control module electrical connector while disconnecting may result in bent or misaligned electrical terminal pins.

3. Test for 4500000 to 5000000 ohms between the test points:Signal circuit terminal 11 & Low: Reference circuit terminal 20

• If not between 4500000 and 5000000 ohms

1. Remove the component:Control Valve Body Cover
2. Disconnect the electrical connector:B14C Transmission Input Shaft Speed Sensor
3. Test for less than 2 ohms between the test points:
   • Control circuit terminal 2@Component harness & Signal circuit terminal 11@Control module harness
   • Low: Reference circuit terminal 1@Component harness & Low: Reference circuit terminal 20@Control module harness
   • If 2 ohms or greater - Replace the component:Automatic Transmission Wiring Harness
   • If less than 2 ohms - Replace the component:B14C Transmission Input Shaft Speed Sensor

• Go to next step: If between 4500000 and 5000000 ohms

4. Test for infinite resistance between the test points:

• Signal circuit terminal 11 & Transmission Case
• Low: Reference circuit terminal 20 & Transmission Case
• If less than infinite resistance

1. Remove the component:Control Valve Body Cover
2. Disconnect the electrical connector:B14C Transmission Input Shaft Speed Sensor
3. Test for infinite resistance between the test points:
   • Signal circuit terminal 2@Component harness & Transmission Case
   • Low: Reference circuit terminal 1@Component harness & Transmission Case
   • If less than infinite resistance - Replace the component:Automatic Transmission Wiring Harness
   • If less than infinite resistance - Replace the component:B14A Transmission Output Shaft Speed Sensor
   • Go to next step: If infinite resistance

• Go to next step: If infinite resistance

5. Replace the component:K71 Transmission Control Module

Component Testing

1. Ignition/Vehicle - Off.

2. Disconnect the electrical connector:B14A Transmission Output Shaft Speed Sensor.

NOTE: The component's temperature should be 19 to 21ºC (66 to 70ºF) while testing.

3. Test for 4500000 to 5000000 ohms between the test points:Control terminal 2 & Low: Reference terminal 1.

• If not between 4500000 and 5000000 ohms

Replace the component:B14A Transmission Output Shaft Speed Sensor

• Go to next step: If between 4500000 and 5000000 ohms

4. Test for infinite resistance between the test points:Each terminal of the component & The component's housing.

• If less than infinite resistance

Replace the component:B14A Transmission Output Shaft Speed Sensor

• Go to next step: If infinite resistance

5. 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 Counter Drive Gear Removal - B14A Transmission Output Shaft Speed Sensor
• Refer to Counter Drive Gear Installation - B14A Transmission Output Shaft Speed Sensor
• Refer to Wiring Harness Wire Replacement - Automatic Transmission Wiring Harness
• For control module replacement, programming, and setup: Refer to Control Module: References

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