2010 Cadillac CTS Sedan AWD V6-3.6L Page 1132

2010 Cadillac CTS Sedan AWD V6-3.6L Page 1132

Circuit/System Testing

Note: You must perform Circuit/System Verification first.

1. Ignition OFF, remove the automatic transmission fluid pan. Refer to Automatic Transmission Fluid, Fluid Pan and/or Filter Replacement ().

2. Disconnect the IMS connector at the Q8 control solenoid valve assembly.

Note: Under certain driving conditions, DTC P182E could set due to an intermittent low voltage fault on the P/N signal circuit, before

conditions for setting DTC P0851 are met.

3. Ignition ON, verify the scan tool engine control module (ECM) P/N switch displays In Gear.

瀚慖f not the specified value, test the P/N signal circuit for a short to ground. If the circuit tests normal, replace the engine control module.

4. Verify the scan tool IMS A/B/C/P parameter displays HI for all four signal circuits.

瀚慖f not the specified value, replace the Q8 control solenoid valve assembly.

5. Connect a 3A fused jumper wire between each transmission range signal circuit terminals listed below and the IMS ground circuit. The

appropriate scan tool IMS A/B/C/P parameter should display LOW when the terminal is connected to the IMS ground circuit.

* Switch Signal A: terminal E to terminal A

* Switch Signal B: terminal D to terminal A

* Switch Signal C: terminal C to terminal A

* Switch Signal P: terminal P to terminal A

瀚慖f not the specified value, replace the Q8 control solenoid valve assembly.

6. If all circuits test normal, test or replace the IMS.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.

Note:

* Perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection (See: Transmission and Drivetrain/Automatic

Transmission/Transaxle/Testing and Inspection/Component Tests and General Diagnostics/Control Solenoid Valve and Transmission Control

Module Assembly Inspection) before replacing any internal transmission components.

* Perform the Service Fast Learn Adapts (See: Transmission and Drivetrain/Automatic Transmission/Transaxle/Testing and

Inspection/Programming and Relearning/Service Fast Learn Adapts) following all transmission repairs.

* 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 internal mode switch (IMS) replacement.

* Control Module References (See: Testing and Inspection/Programming and Relearning) for control solenoid valve assembly replacement,

setup, and programming.

P0191

DTC P0191 (w/LLT)

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 P0191

- Fuel Rail Pressure Sensor Performance

Diagnostic Fault Information