2010 Cadillac CTS Sedan AWD V6-3.0L Page 1677
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 P0842
- Transmission Fluid Pressure (TFP) Switch 1 Circuit Low Voltage
DTC P0843
- Transmission Fluid Pressure (TFP) Switch 1 Circuit High Voltage
Diagnostic Fault Information
Typical Scan Tool Data
Circuit/System Description
The transmission fluid pressure (TFP) switch 1 is part of the control solenoid valve assembly which has no serviceable parts. The TCM supplies a
signal circuit to the TFP Switch 1. The TFP Switch 1 has an internal case ground. TFP Switch 1 is normally closed or LOW. When oil pressure is
present at the TFP Switch 1, the switch is open or HIGH. The normally high clutch pressure control (PC) solenoid 2 controls pressure to the 3-5
reverse clutch regulator valve. The TCM monitors the TFP switch 1 to determine the position of the 3-5 reverse clutch regulator valve. When the
3-5 reverse clutch is commanded OFF, pressure is present on the TFP switch 1. When the 3-5 reverse clutch is commanded ON, the 3-5 reverse
clutch regulator valve moves and pressure to the TFP switch 1 is exhausted through the 3-5 reverse clutch regulator valve.
Conditions for Running the DTC
P0842 or P0843
* DTCs P0751, P0752, P0756, P0757, P0973, P0974, P0977, P1825 or P1915 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
P0842
The TCM detects that the TFP switch 1 signal voltage remains LOW after the 3-5-R clutch transitions from a HIGH pressure state to a LOW
pressure state. The TCM counts each incident. The DTC sets when 35 counts are accumulated.
P0843
The TCM detects that the TFP switch 1 signal voltage remains HIGH after the 3-5-R clutch transitions from a LOW pressure state to a HIGH
pressure state. The TCM counts each incident. The DTC sets when 25 counts are accumulated.
Action Taken When the DTC Sets
* DTCs P0842 and P0843 are Type C DTCs.
* The TCM freezes transmission adaptive functions.
