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P1810




DTC P1810, P1816, or P1818

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC P1810
- Transmission Fluid Pressure (TFP) Position Switch Circuit

DTC 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





Typical Scan Tool Data






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 a reference 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. Refer to Transmission Fluid Pressure Manual Valve Position Switch Logic (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 Nm (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 Nm (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 (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 (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.
* EL-49742 harness is a good source for B+ and ground.

Reference Information
Schematic Reference

Automatic Transmission Controls Schematics (Electrical Diagrams)
Connector End View Reference

* Component Connector End Views (Connector End Views By Name)
* Inline Harness Connector End Views (Connector End Views By Number)

Description and Operation

Electronic Component Description (Electronic Component Description)for automatic transmission fluid pressure manual valve position switch assembly information
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Powertrain Diagnostic Trouble Code (DTC) Type Definitions)
Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information
Special Tools

* EL-49742 Battery Voltage B+ and Ground Source Harness
* J 44152 Jumper Harness (20 pins)
* J 44257 Main Wiring Harness Connector Remover

Circuit/System Verification

1. Perform the Transmission Fluid Level and Condition Check (Transmission Fluid Level and Condition Check).
2. 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 (Transmission Fluid Pressure Manual Valve Position Switch Logic) table. The parameter should match each gear range that is selected.
3. 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.
4. 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.

Circuit/System Testing

Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.


1. Ignition OFF, using the Main Wiring Harness Connector Remover J 44257 , disconnect the automatic transmission (AT) inline 20-way pass-thru connector.
2. Install the J 44152 jumper harness on the engine side of the AT in-line 20-way pass-thru connector.
3. Key ON. Engine OFF. Observe the scan tool TFP Sw. Sig. B/ Sig. C parameter. The reading should display HI/HI.

• If not the specified value, test the affected signal circuit for a short to ground. If all circuits and connections test normal, replace the TCM.

4. Using the BN probe J 35616-7, test for B+ (0.0/-1.0V) between each signal circuit, jumper harness terminals R, P, U and a good ground. Jumper harness EL-49742 is a good source for B+ and ground.

• If less than the specified value, test the affected signal circuit for an open/high resistance. If all circuits and connections test normal, replace the TCM.

5. Install a 3 A fused jumper wire between the TFP switch signal B circuit, jumper harness terminal R, and a good ground. Verify that the scan tool TFP Sw. Sig. B/ Sig. C parameters change from HI/HI when open to LOW/HI when grounded.

• If not the specified value, test the TFP switch signal B circuit for an open/high resistance. If all circuits and connections test normal, replace the TCM.

6. Install a 3 A fused jumper wire between the TFP switch signal C circuit, jumper harness terminal P, and a good ground. Verify that the scan tool TFP Sw. Sig. B/ Sig. C parameters change from HI/HI when open to HI/LOW when grounded.

• If not the specified value, test the TFP switch signal C circuit for an open/high resistance. If all circuits and connections test normal, replace the TCM.

7. Install a 3 A fused jumper wire between the TCC Release Switch Signal circuit, jumper harness terminal U, and a good ground. Verify that the scan tool TCC Release Pressure parameter changes from YES when open to NO when grounded.

• If not the specified value, test the TFP switch signal C circuit for an open/high resistance. If all circuits and connections test normal, replace the TCM.

8. If all circuits and connections test normal, go to Component Testing.

Component Testing

1. Ignition OFF, using the Main Wiring Harness Connector Remover J 44257 , disconnect the automatic transmission (AT) inline 20-way pass-thru connector.
2. Install the J 44152 jumper harness on the engine side of the AT in-line 20-way pass-thru connector.
3. Apply parking brake. Key ON. Engine ON.
4. Apply foot brake.
5. Transmission in Reverse. Using the BN probe J 35616-6, test for greater than 1M ohm between the Transmission Fluid Pressure Switch Signal B, jumper harness pin R and a good ground. Jumper harness EL-49742 is a good source for B+ and ground.

• If less than the specified value, test the signal circuit for a short to ground. If the internal transmission harness is shorted to ground, replace the internal transmission harness. If the internal transmission harness tests normal, replace the TFP switch.

6. Transmission in Drive. Using the BN probe J 35616-6, test for less than 100K ohm between the Transmission Fluid Pressure Switch Signal B, jumper harness pin R and a good ground.

• If greater than the specified value, test the signal circuit for an open. If the internal transmission harness is open, replace the internal transmission harness. If the internal transmission harness tests normal, replace the TFP switch.

7. Transmission in Reverse. Using the BN probe J 35616-6, test for less than 100K ohm between the Transmission Fluid Pressure Switch Signal C, jumper harness pin P and a good ground.

• If greater than the specified value, test the signal circuit for an open. If the internal transmission harness is open, replace the internal transmission harness. If the internal transmission harness tests normal, replace the TFP switch.

8. Transmission in Drive. Using the BN probe J 35616-6, test for greater than 1M ohm between the Transmission Fluid Pressure Switch Signal C, jumper harness pin P and a good ground.

• If less than the specified value, test the signal circuit for a short to ground. If the internal transmission harness is shorted to ground, replace the internal transmission harness. If the internal transmission harness tests normal, replace the TFP switch.

9. Key OFF.
10. Using the BN probes J 35616-6, test for greater than 1M ohm between the Transmission Fluid Pressure Switch Signal B, jumper harness pin R, and all other pins of the J 44152 jumper harness.

• If the resistance is less than the specified range, test the affected circuits for a shorted together condition. If the internal transmission harness is shorted together, replace the internal transmission harness.

11. Using the BN probes J 35616-6, test for greater than 1M ohm between the Transmission Fluid Pressure Switch Signal C, jumper harness pin P and all other pins of the J 44152 jumper harness.

• If the resistance is less than the specified range, test the affected circuits for a shorted together condition. If the internal transmission harness is shorted together, replace the internal transmission harness.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.

* Wiring Harness Replacement (Service and Repair)
* Transmission Fluid Pressure Manual Valve Position Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for TCM replacement, setup, and programming.

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