| Table 1: | TFP Valve Position Switch Logic Table |
| Table 2: | P1810 |
Circuit Description
The Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) consists of six pressure switches. Five of the switches are normally-open, and determine gear range selection. The sixth switch is normally-closed, and detects Torque Converter Clutch (TCC) release fluid pressure. The TFP Val. Position Sw. also contains the Automatic Transmission Fluid Temperature (TFT) sensor. These components are combined into one unit, mounted on the valve body.
The Powertrain Control Module (PCM) provides battery voltage on the three range signal circuits. By grounding one or more of the switches with fluid pressure from the manual shift valve, the PCM detects the selected gear range. When you disconnect the transmission electrical connector and the ignition is ON, the ground potential for three range signals from the PCM will be removed, and an illegal gear will be indicated (Refer to the TFP Val. Position Sw. Logic table).
When the PCM detects any of the following conditions, DTC P1810 sets.
| • | An invalid gear state |
| • | A drive range after start up |
| • | An incorrect gear ratio |
DTC P1810 is a type A DTC.
Conditions for Setting the DTC
DTC P1810 sets when any one of the following three conditions occur:
Condition 1
| • | The engine is running. |
| • | The gear range is illegal for 5 seconds (Refer to the TFP Val. Position Sw. Logic table). |
Condition 2
| • | The engine speed is in transition from 0 RPM to greater than 500 RPM. |
| • | The system voltage is 10-16 volts. |
| • | No VSS DTC P0502 |
| • | The vehicle speed is less than 11 km/h (7 mph). |
| • | D2, D4, or Reverse gear is indicated after start-up for 2 seconds. |
Condition 3
| • | The engine is running. |
| • | No TP Sensor DTCs P0121, P0122, or P0123 |
| • | No VSS DTC P0502 |
| • | No Input Speed Sensor DTCs P0716 or P0717 |
| • | No illegal gear ranges detected (Refer to the TFP Val. Position Sw. Logic table). |
| • | The vehicle speed is at least 16 km/h (10 mph). |
| • | The TP is at least 15%. |
And any one of the following three conditions occurs:
| • | The TFP Val. Position Sw. indicates Park/Neutral when the gear ratio is less than 1:0.72 (4th gear) for 10 seconds. |
| • | The TFP Val. Position Sw. indicates Reverse when the gear ratio is greater than 1:2.23, or less than 1:2.02, for 5 seconds. |
| • | The TFP Val. Position Sw. indicates D, 3, 2, or 1 when the gear ratio indicates Reverse for 10 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM assumes a D4 shift pattern. |
| • | The PCM elevates line pressure. |
| • | DTC P1810 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | A pressure regulator problem could set DTC P1810. |
| • | Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| • | When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change. |
Gear Position | Range Signal A | Range Signal B | Range Signal C |
|---|---|---|---|
PARK | ON | OFF | OFF |
REVERSE | ON | OFF | ON |
NEUTRAL | ON | OFF | OFF |
DRIVE/OD | ON | ON | OFF |
D3/3rd | OFF | ON | OFF |
D2/2nd | OFF | ON | ON |
D1/Lo | ON | ON | ON |
Illegal | OFF | OFF | OFF |
Illegal | OFF | OFF | ON |
Test Description
The numbers below refer to the Step numbers on the diagnostic table.
-
This Step tests the PCM's ability to recognize an open circuit on signal A, B, and C ranges.
-
This Step verifies signal A circuit from the PCM.
-
This Step verifies signal B circuit from the PCM.
-
This Step verifies signal C circuit from the PCM.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 2.3L | |||||
2 | Have you performed the transmission fluid checking procedure? | -- | Go to Transmission Fluid Check | |||||
3 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data. Refer to the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) Logic table. Does each selected transmission range match the scan tool display? | -- | Go to Diagnostic Aids | |||||
4 |
Does the TFP Switch display match the specified values? | A Off B Off C Off | ||||||
5 | Does TFP Switch indicate range signal A is On? | -- | ||||||
6 | Does TFP Switch indicate range signal B is On? | -- | ||||||
7 | Does TFP Switch indicate range signal C is On? | -- | -- | |||||
8 | Inspect circuit 1224 to the engine harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
9 | Inspect circuit 1225 of the engine harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
10 | Inspect circuit 1226 of the engine harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
11 |
Important: If, while performing Steps 11, 12, or 13, two (or more) signal ranges indicate On, those circuits are shorted together.
Does the TFP Switch indicate signal A is On? | A On | ||||||
12 | Connect the fused jumper wire from terminal R to a good ground. Does the TFP Switch indicate signal B is On? | B On | ||||||
13 | Connect the fused jumper wire from terminal P to a good ground. Does the TFP Switch indicate signal C is On? | C On | ||||||
14 | Inspect circuit 1224 of the engine harness for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
15 | Inspect circuit 1225 of the engine harness for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
16 | Inspect circuit 1226 of the engine harness for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
17 |
Is the circuit resistance greater than the specified value? | 1000ohms | ||||||
18 | Connect the ohmmeter from terminal R to a good ground. Is the circuit resistance greater than the specified value? | 1000ohms | ||||||
19 | Connect the ohmmeter from terminal P to a good ground. Is the circuit resistance greater than the specified value? | 1000ohms | ||||||
20 | Inspect circuit 1224 of the transmission harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
21 | Inspect circuit 1225 of the transmission harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
22 | Inspect circuit 1226 of the transmission harness for a short to ground. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
23 | Inspect circuit 1224 from the Automatic Transmission 20-way connector to the TFP Val. Position Sw. for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
24 | Inspect circuit 1225 from the Automatic Transmission 20-way connector to the TFP Val. Position Sw. for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
25 | Inspect circuit 1226 from the transmissionAutomatic Transmission 20-way connector to the TFP Val. Position Sw. for an open. Refer to Troubleshooting Procedures, Section 8. Did you find and correct the condition? | -- | ||||||
26 | Replace the TFP Val. Position Sw. Refer to Automatic Transmission Fluid Pressure Manual Valve Position Switch Replacement, in On-Vehicle Service. Is the replacement complete? | -- | -- | |||||
27 | Replace the PCM. Refer to Section 6: Powertrain Control Module/EEPROM Replacement/Programming in Engine Controls - 2.3L Is the replacement complete? | -- | -- | |||||
28 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
