Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC P0842: Transmission Fluid Pressure (TFP) Switch 1 Circuit Low VoltageDTC P0843: Transmission Fluid Pressure (TFP) Switch 1 Circuit High Voltage
DTC P0872: Transmission Fluid Pressure (TFP) Switch 3 Circuit Low Voltage
DTC P0873: Transmission Fluid Pressure (TFP) Switch 3 Circuit High Voltage
DTC P0877: Transmission Fluid Pressure (TFP) Switch 4 Circuit Low Voltage
DTC P0878: Transmission Fluid Pressure (TFP) Switch 4 Circuit High Voltage
DTC P0989: Transmission Fluid Pressure (TFP) Switch 5 Circuit Low Voltage
DTC P0990: Transmission Fluid Pressure (TFP) Switch 5 Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
TFP Switch 1 Signal | P0842 | P0843 | P0843 |
TFP Switch 3 Signal | P0872 | P0873 | P0873 |
TFP Switch 4 Signal | P0877 | P0878 | P0878 |
TFP Switch 5 Signal | P0989 | P0990 | P0990 |
Typical Scan Tool Data
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: 12 Volts = Hi, 0 Volts = Low | |||
TFP Switch 1 | Low | Hi | Hi |
TFP Switch 3 | Low | Hi | Hi |
TFP Switch 4 | Low | Hi | Hi |
TFP Switch 5 | Low | Hi | Hi |
Circuit/System Description
The transmission fluid pressure (TFP) switch assembly is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The transmission control module (TCM) supplies 12 volts to each TFP switch via its respective signal circuit. The TFP switch assembly has an internal case ground. Each TFP switch is normally closed, Low. When oil pressure is present at the TFP switch, the switch is Open, High. The TCM monitors each normally closed TFP switch signal circuit to determine clutch status.
Conditions for Running the DTC
| • | No TFT DTCs P0711, P0712, or P0713. |
| • | No pressure control solenoid electrical DTCs P0965, P0966, P0967, P0969, P0970, P0971, P2719, P2720, P2721, P2728, P2729, or P2730. |
| • | No shift solenoid electrical DTCs P0973, P0974, P0976, or P0977. |
| • | No IMS DTCs P1825 or P1915. |
| • | The engine speed is 1,100 RPM or greater. |
| • | Ignition voltage is between 9.0 volts and 19.0 volts. |
| • | The transmission fluid temperature (TFT) is 20-150°C (68-302°F). |
Conditions for Setting the DTC
P0842
The TCM detects that the TFP switch 1 signal voltage remains low, 0 volts when the 3-5-R clutch is commanded ON for 20 seconds or greater.
P0843
The TCM detects that the TFP switch 1 signal voltage is high, 12 volts when the 3-5-R clutch is commanded OFF for 20 seconds or greater.
P0872
The TCM detects that the TFP switch 3 signal voltage remains low, 0 volts when the 2-6 clutch is commanded ON for 20 seconds or greater.
P0873
The TCM detects that the TFP switch 3 signal voltage is high, 12 volts when the 2-6 clutch is commanded OFF for 20 seconds or greater.
P0877
The TCM detects that the TFP switch 4 signal voltage remains low, 0 volts when the 1-2-3-4 clutch is commanded ON for 20 seconds or greater.
P0878
The TCM detects that the TFP switch 4 signal voltage is high, 12 volts when the 1-2-3-4 clutch is commanded OFF for 20 seconds or greater.
P0989
The TCM detects that the TFP Switch 5 signal voltage remains low, 0 volts when the low and reverse/4-5-6 clutch is commanded ON for 20 seconds or greater.
P0990
the TCM detects that the TFP Switch 5 signal voltage is high, 12 volts when the low and reverse/4-5-6 clutch is commanded OFF for 20 seconds or greater.
Action Taken When the DTC Sets
| • | DTCs P0842, P0843, P0872, P0873, P0877, P0878, P0989, and P0990 are Type C DTCs. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DTC
DTCs P0842, P0843, P0872, P0873, P0877, P0878, P0989, and P0990 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- If there are any other transmission related DTCs set, diagnose those DTCs first. Refer to Diagnostic System Check - Vehicle.
- Engine idling, parking brake applied, range selector in L (M), command the Shift Transmission with a scan tool to achieve 2nd gear.
- Observe the suspect scan tool TFP Switch parameter while commanding the Shift Transmission with a scan tool to achieve 5th gear. Each TFP Switch parameter should toggle states (from High to Low or Low to High) between 2nd and 5th gear.
| ⇒ | If the specified parameter does not toggle, replace the control solenoid (w/body and TCM) valve assembly. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| Note: Before replacing the TCM, perform the Control Solenoid Valve and Transmission Control Module Assembly Inspection. |
| • | Control Module References for control solenoid (w/body and TCM) valve assembly replacement, setup, and programming. |
| • | Perform the Service Fast Learn Adapts following all transmission related repairs. |
