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Tahoe / Yukon Service Manual

DTC P187D, P187E, P18E7, or P18E8

Automatic Transmission - 10L80 MHS MQC | Diagnostic Information and Procedures | Document ID: 5224809 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P187D Transmission Park Valve Stuck On DTC P187E Transmission Park Valve Stuck Off DTC P18E7 Transmission Park Valve Position Sensor Performance DTC P18E8 Transmission Park Valve Position Sensor 2 Performance Diagnostic Fault Information

Component DTC Condition
Control Valve Body Default Disable Valve Electronic Transmission Range Select (ETRS) Valve Park Servo Valve Reverse to Park (RTP) Blow Off Valve P187D, P187E, P18E7, P18E8 Binding or Sticking Debris on the component. Mechanically damaged Missing components
M123 Transmission Park Valve Lock Solenoid Actuator / Park Inhibit Solenoid P187D, P187E, P18E7, P18E8 Binding or Sticking Debris on the component. Mechanically damaged Missing components

Circuit/System Description For an overview of the component/system, refer to: Park - Engine Running Reverse Neutral - Engine Running Drive Range, First Gear Drive Range, Second Gear Drive Range, Third Gear Drive Range, Fourth Gear Drive Range, Fifth Gear Drive Range, Sixth Gear Drive Range, Seventh Gear Drive Range, Eighth Gear Drive Range, Ninth Gear Drive Range, Tenth Gear Electronic Component Description Conditions for Running the DTC DTC P2534 = Not set DTCs related to the following system/component = Not Set – B14A Automatic Transmission Output Speed Sensor – B14C Automatic Transmission Input Speed Sensor – B14DA Automatic Transmission Intermediate Speed Sensor 1 – B14DB Automatic Transmission Intermediate Speed Sensor 2 – B303 Transmission Range Sensor – Transmission Control Solenoid Valves — Circuit DTCs Battery Voltage = Greater than 9 V Engine = Running High Side Driver 1, 2 = On Ignition and Start Signal = 9 to 32 V Ignition and Start Switch Signal = On Scan Tool Control Function = Not Activated Transmission Range = D, L or M One of the following conditions listed below is true: – Accelerator Pedal Position = Greater than 0.5% – Engine Speed = Greater than 1,000 RPM – Transmission Input Speed = Greater than 349 RPM – Transmission Output Shaft Speed = Greater than 35 RPM Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC B316 Transmission Park Valve Position Switch = Commanded state does not match the actual state Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A DTC Reference Information Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification

  1. 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 ⇓ If no condition exists
  2. Ignition » On / Vehicle » In Service Mode
  3. Perform the following action: Clear the DTCs.
  4. 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. Refer to: Road Test Verify that no DTC listed in the DTC Descriptor Category is set. ⇒ If any of the DTCs are set Refer to: Diagnostic Fault Information & Verify the conditions listed in the table do not exist ⇓ If none of the DTCs are set
  5. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Control Valve Assembly Assemble Control Valve Assembly Disassemble Control Valve Body Replacement For control module replacement, programming, and setup refer to: Control Module References