Diagnostic Instructions
DTC Descriptors
DTC P0877: Transmission Fluid Pressure (TFP) Switch 4 Circuit Low Voltage
DTC P0878: Transmission Fluid Pressure (TFP) Switch 4 Circuit High Voltage
Circuit/System Description
The transmission fluid pressure (TFP) switch 4 is part of the control solenoid (w/body and TCM) valve assembly and is not serviced separately. The TCM supplies 12 volts to the TFP switch 4 on the TFP switch 4 signal circuit;
the TFP switch 4 has an internal case ground. TFP switch 4 is normally closed, Low. When oil pressure is present at the TFP switch 4, the switch is open, high. The normally low clutch pressure control (PC) solenoid 5 controls
the transmission fluid to the 1-2-3-4 clutch. The TCM monitors the normally closed TFP switch 4 signal circuit to determine the 1-2-3-4 clutch status.
Conditions for Running the DTC
| • | DTCs P0711, P0712 or P0713 are not set. |
| • | No DTCs P0965, P0966, P0967, P0968, P0969, P0970, or P0971 |
| • | No DTCs P0973, P0974, P0976, P0977, P2719, P2720, P2728, P2729, or P2730. |
| • | The transmission fluid temperature (TFT) is between 20 and 150°C (68 and 302°F). |
| • | The engine speed is greater than or equal to 1,100 RPM. |
Conditions for Setting the DTC
P0877
| - | The TCM does not turn off during the process. |
| - | Pressure control solenoid 5 hydraulic pressure is less than or equal to 100 kPa for 0.45 seconds. |
| - | The pressure switch remain closed for 5.5 seconds. |
P0878
| - | The TCM does not turn off during the process. |
| - | The PC solenoid valve 5 hydraulic is 600 kPa or greater for 1 second. |
| - | Keep the pressure switch OFF for 5.5 seconds. |
Action Taken When the DTC Sets
| • | DTCs P0877 and P0878 are Type C DTCs. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DTC
DTCs P0877 and P0878 are Type C DTCs.
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
DTC Type Reference
Electrical Information Reference
Circuit/System Verification
If there are any other transmission related DTCs set, diagnose those DTCs first.
Circuit/System Testing
- Ensure the TFT is near the temperature displayed in the Failure Records.
- Start the engine and place the transmission range selector in D6.
- Observe the TFP switch 4 parameter while commanding 4th gear and then commanding 5th gear with the scan tool. The TFP Switch 4 should transition from High in 4th gear to Low in 5th gear.
| ⇒ | If no concerns are found, replace the control solenoid (w/body and TCM) valve assembly. |
Component Testing
Perform the
Control Solenoid Valve and Transmission Control Module Assembly Inspection
.
Repair Instructions
Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
