P1808
DTC P1808 or P1809 (2.4L Hybrid)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
DTC Descriptors
DTC P1808
- Transmission Fluid Pressure (TFP) Position Switch - Stuck Off
DTC P1809
- Transmission Fluid Pressure (TFP) Position Switch - Stuck On
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.
Conditions for Running the DTC
P1808
* No CKP DTCs P0335 or P0336.
* The engine is running for 5 seconds.
P1809
* The power mode is not Run or Crank.
* The engine has not been running for 5.5 seconds.
* The vehicle speed is 0 km/h (0 mph).
Conditions for Setting the DTC
P1808
The ECM determines from communications with the TCM that the TFP signal B circuit is open or stuck OFF.
P1809
The ECM determines from communications with the TCM that the TFP signal B circuit is shorted to ground or stuck ON.
Action Taken When the DTC Sets
DTCs P1808 and P1809 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P1808 and P1809 are Type B DTCs.
Diagnostic Aids
Transmission Fluid Pressure Manual Valve Position Switch Logic (Transmission Fluid Pressure Manual Valve Position Switch Logic)
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics (MN5) (Electrical Diagrams)Automatic Transmission Controls Schematics (ME7) (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
J 44152 Jumper Harness (20 pins)
Circuit/System Verification
Ignition ON, engine running observe the scan tool TFP Switch while moving the shift lever through the full selection range. The reading should change between Park/Neutral, Reverse, Drive for each corresponding gear.
Circuit/System Testing
Important: Additional DTCs may set when disconnecting the automatic transmission inline 20-way connector.
1. Ignition OFF, disconnect the harness connector at the automatic transmission.
Disconnect the automatic transmission (AT) inline 20-way connector at the transmission.
2. Ignition ON, observe the scan tool Sig. B/Sig. C parameter. The Sig. B reading should be HI.
• If not the specified value, test for a short to ground between terminal 44 and terminal R. If the circuit tests normal replace the TCM.
3. Install a 3A fused jumper wire between the signal circuit terminal R and ground. Verify the scan tool parameter Sig. B is LOW.
• If not the specified value, test the signal circuit between terminal R to terminal 44 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the TCM.
4. Test for less than 1 ohm of resistance between terminal R of the AT 20-way connector and terminal B of the TFP manual valve position switch.
• If greater than the specified range, replace the Internal Transmission Harness.
5. If all circuits test normal, test or replace the TFP Manual valve Position switch.
Component Testing
1. Ignition OFF, disconnect the harness connector at the automatic transmission.
2. Test for less than 1 ohm resistance between the signal circuit terminal R and the ground circuit terminal B.
• If greater then the specified value, replace the internal transmission harness.
3. Test for infinite resistance between terminal R and all other terminals of the AT side 20-way connector.
• If not the specified value, replace the automatic transmission wiring harness.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the repair.
* Transmission Fluid Pressure Manual Valve Position Switch Replacement (Service and Repair)
* Wiring Harness Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for TCM replacement, setup, and reprogramming