2010 Cadillac CTS Sedan AWD V6-3.0L Page 1684
9. Disconnect the B15 automatic transmission internal mode switch electrical connector from the K71 TCM.
10. Ignition ON, test for 11-13 volts between terminal F on the K71 TCM and ground at the transmission case.
瀚慖f not within the specified range, replace the Q8 control solenoid valve assembly.
11. If all circuits test normal, replace the B15 automatic transmission internal mode switch.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Control Module References (See: Testing and Inspection/Programming and Relearning) for control solenoid valve assembly or ECM
replacement, setup, and programming.
Note: If the IMS switch has been replaced, inspect the valve body detent spring to be sure it is centered over the detent lever. This prevents
the detent spring from hitting the IMS switch.
* Manual Shift Shaft Position Switch Replacement (See: Powertrain Management/Computers and Control Systems/Sensors and Switches -
Computers and Control Systems/Transmission Position Sensor/Switch/Service and Repair/Manual Shift Shaft Position Switch Replacement)
for IMS replacement.
P0852
DTC P0850-P0852
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0850
- Park/Neutral Position (PNP) Switch Circuit
DTC P0851
- Park/Neutral Position (PNP) Switch Circuit Low Voltage
DTC P0852
- Park/Neutral Position (PNP) Switch Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The transmission manual shift shaft switch assembly, also known as the internal mode switch (IMS), is a sliding contact switch attached to the
manual shift shaft inside the transmission case. The park/neutral position (PNP) switch is integrated into the IMS and connects to the transmission
control module (TCM) lead-frame through a short wire harness. The circuit uses the TCM as a pass-through connector only.
The Park/Neutral Signal is sent from the park/neutral switch directly to the engine control module (ECM) and is used for engine start enable.
Conditions for Running the DTC
