2010 Cadillac CTS Sedan AWD V6-3.0L Page 1695

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1695

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 P0877

- Transmission Fluid Pressure (TFP) Switch 4 Circuit Low Voltage

DTC P0878

- Transmission Fluid Pressure (TFP) Switch 4 Circuit High Voltage

Diagnostic Fault Information

Typical Scan Tool Data

Circuit/System Description

The transmission fluid pressure (TFP) switch 4 is part of the control solenoid valve assembly which has no serviceable parts. The TCM supplies a

signal circuit to the TFP switch 4. The TFP switch 4 has an internal case ground. TFP switch 4 is normally closed or LOW. When oil pressure is

present at the TFP switch 4, the switch is open or HIGH. The normally LOW pressure control solenoid 5 controls pressure to the 1-2-3-4 clutch

regulator valve. The TCM monitors the TFP switch 4 to determine the position of the 1-2-3-4 clutch regulator valve. When the 1-2-3-4 clutch is

commanded OFF, pressure is present on the TFP switch 4. When the 1-2-3-4 clutch is commanded ON, the 1-2-3-4 clutch regulator valve moves

and pressure to the TFP switch is exhausted through the 1-2-3-4 clutch regulator valve.

Conditions for Running the DTC

P0877 or P0878

* DTCs P0711, P0712, P0713, P0973, P0974, P0976, P0977, P1915, or P182E are not set.

* Ignition voltage is 8.6 volts or greater.

* The transmission fluid temperature (TFT) is 0-120掳C (32-248掳F).

* Engine speed is 500 RPM or greater for 5 seconds.

Conditions for Setting the DTC

P0877

The TCM detects that the TFP switch 4 signal voltage remains LOW after the 1-2-3-4 clutch transitions from a HIGH pressure state to a LOW

pressure state. The TCM counts each incident. The DTC sets when 20 counts are accumulated.

P0878

The TCM detects that the TFP switch 4 signal voltage remains HIGH after the 1-2-3-4 clutch transitions from a LOW pressure state to a HIGH

pressure state. The TCM counts each incident. The DTC sets when 18 counts are accumulated.

Action Taken When the DTC Sets

* DTCs P0877 and P0878 are Type C DTCs.

* The TCM freezes transmission adaptive functions.