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 P1810: Transmission Fluid Pressure (TFP) Position Switch CircuitDTC P1816: Transmission Fluid Pressure (TFP) Valve Position Switch Indicates Park/Neutral (P/N) with Drive Ratio
DTC P1818: Transmission Fluid Pressure (TFP) Valve Position Switch Indicates Drive without Drive Ratio
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|
TFP Switch Signal B | P1810, P1816, P1818 | P1816 | -- |
TFP Switch Signal C | P1810, P1816, P1818 | P1810, P1816, P1818 | -- |
Typical Scan Tool Data
Circuits | Normal | Short to Ground | Open/High Resistance | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: Engine running, normal operating temperature Parameter Normal Range: HI/HI | ||||
TFP Sig B. | HI/HI | LOW/HI | HI/HI | HI/HI |
TFP Sig C. | HI/HI | HI/LOW | HI/HI | HI/HI |
Circuit/System Description
The automatic transmission fluid pressure (TFP) manual valve position switch consists of three pressure switches. two of the switches are normally-open, and determine gear range selection. The third switch is normally-closed, and detects torque converter clutch (TCC) release fluid pressure. The TFP manual valve position switch also contains the automatic transmission fluid temperature (TFT) sensor. These components are combined into one unit, attached to the control valve body. The transmission control module (TCM) provides battery voltage on the two range signal circuits. By grounding one or more of the switches with fluid pressure from the manual shift valve, the TCM detects the selected gear range. When you disconnect the transmission electrical connector and the ignition is ON, the ground potential for the range signals from the TCM will be removed, and an invalid gear range will be indicated. Refer to Transmission Fluid Pressure Manual Valve Position Switch Logic .
Conditions for Running the DTC
P1810
The engine is running for 5 seconds.
P1816
| • | No TP DTCs P0120 or P0220. |
| • | No ISS DTCs P0716 or P0717. |
| • | No OSS DTCs P0722 or P0723. |
| • | No SS valve performance DTCs P0751, P0752, P0756, or P0757. |
| • | No SS valve electrical DTCs P0973 or P0974, P0976, or P0977. |
| • | The engine is running for 5 seconds. |
| • | The Calc. Throttle Position is between 8 percent and 90 percent. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
| • | The output speed is 250 RPM or more. |
P1818
| • | No MAP DTCs P0107 or P0108. |
| • | No TP DTCs P0120 or P0220. |
| • | No ISS DTCs P0716 or P0717. |
| • | No OSS DTCs P0722 or P0723. |
| • | No SS valve performance DTCs P0751, P0752, P0756, or P0757. |
| • | No SS valve electrical DTCs P0973 or P0974, P0976, or P0977. |
| • | The engine is running for 5 seconds. |
| • | The Calc. Throttle Position is 10 percent or more. |
| • | The engine torque is greater than 45 N·m (33 lb ft). |
| • | The output speed is 153 RPM or more. |
| • | The transmission fluid temperature is greater than 20°C (68°F). |
Conditions for Setting the DTC
P1810
The TCM detects an invalid gear range for 60 seconds. Refer to Transmission Fluid Pressure Manual Valve Position Switch Logic .
P1816
The TCM detects P/N with a drive ratio for 6 seconds.
P1818
The TCM detects a PARK, NEUTRAL, or a drive range with a REVERSE ratio for 3 seconds.
Action Taken When the DTC Sets
| • | DTCs P1810, P1816, and P1818 are Type B DTCs. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
Conditions for Clearing the DTC
DTCs P1810, P1816, and P1818 are Type B DTCs.
Diagnostic Aids
| • | Refer to Transmission Fluid Pressure Manual Valve Position Switch Logic for the normal range signals and the invalid combinations. On the table, LOW is 0 volts, HI is ignition voltage. |
| • | Sediment in the valve body may cause improper operation of the TFP manual valve position switch. If sediment intrusion is suspected, clean the valve body and replace the TFP manual valve position switch. |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Description and Operation
Electronic Component Description for automatic transmission fluid pressure manual valve position switch assembly information
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 44152 Jumper Harness (20 pins)
Circuit/System Verification
- Perform the Transmission Fluid Check to verify correct fluid level and condition. The transmission fluid level should be within the crosshatch band and the transmission fluid should be red or dark brown.
- Engine idling, observe the scan tool TFP Sw. Sig. B/ Sig. C parameter while moving the gear shift lever from Park, to Reverse and through all the gear ranges and compare to the Transmission Fluid Pressure Manual Valve Position Switch Logic table. The parameter should match each gear range that is selected.
- Observe the scan tool TFP Sw. parameter while moving the gear shift lever from Park, to Reverse and through all the gear ranges. The selected transmission gear range should match the scan tool TFP Sw. display.
- Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
| ⇒ | If the transmission fluid is low or discolored, refer to Automatic Transmission Fluid Filter and Seal Replacement . |
Circuit/System Testing
- Ignition OFF, disconnect the automatic transmission inline 20-way connector at the transmission.
- Install the J 44152 on the engine side of the AT inline 20-way connector.
- Ignition ON, observe the scan tool TFP Sw. Sig. B/ Sig. C parameter. The reading should display HI/HI.
- Test for B+ between each signal circuit terminals R, P, U and ground.
- If all circuits test normal, test the internal transmission wiring harness assembly and the TFP switch.
Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.
| ⇒ | If not the specified value, test the appropriate signal circuit for a short to ground. If the circuits test normal, replace the TCM. |
| ⇒ | If less than the specified value, test the appropriate signal circuit for an open/high resistance. If the circuits test normal, replace the TCM. |
Component Testing
- Ignition OFF, disconnect the automatic transmission (AT) 20-way connector at the transmission.
- Install the J 44152 on the transmission side of the AT 20-way connector.
- Test the signal B circuit terminal R for less than 10 ohms of resistance with the transmission in park and infinite resistance with transmission in Drive.
- Test the signal C circuit terminal P for less than 10 ohms of resistance with the transmission in Drive and infinite resistance with transmission in Park.
| ⇒ | If not the specified value, test the signal circuit for a short to ground, a short to voltage, or open/high resistance. If a circuit is shorted or open, replace the internal transmission wiring harness assembly, if the circuits test normal, replace the TFP switch. |
| ⇒ | If not the specified value, test the signal circuit for a short to ground, a short to voltage, or open/high resistance. If a circuit is shorted or open, replace the internal transmission wiring harness assembly, if the circuits test normal, replace the TFP switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
| • | Control Module References for TCM replacement, setup, and programming. |
