| Table 1: | TFP Manual Valve Position Switch Logic |
| Table 2: | DTC P1810 Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch Circuit Malfunction |
Circuit Description
The Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch consists of five pressure switches (two normally-closed and three normally-open), and an automatic transmission fluid temperature (TFT) sensor. The combined unit mounts on the valve body. The PCM supplies battery voltage to each range signal. The PCM grounds one or more of the range signal circuits through various combinations of the pressure switches. The PCM monitors the combinations, in order to detect what manual valve position has been selected. The PCM compares the actual voltage combination of the switches to a TFP Valve Position Switch combination chart stored in the memory.
The TFP Valve Position Switch cannot distinguish between Park and Neutral because the monitored valve body pressures are identical. With the ignition ON and the engine OFF, the valve pressures indicate Park or Neutral. Disconnecting the transmission 20-way connector, removes the ground potential for the three range signals to the PCM. This disconnected state, with the ignition ON, displays as D2.
DTC P1810 detects an invalid state of the TFP Valve Position Switch or the TFP Val Position Sw. circuit. DTC P1810 deciphers the TFP Val Position Sw. inputs. DTC P1810 is a type B DTC.
Conditions for Setting the DTC
DTC P1810 sets if any of the following Conditions occurs:
Condition 1:
This condition detects an illegal switch combination.
| • | No system voltage DTC P0560 |
| • | The engine is running. |
| • | The PCM detects an illegal TFP state. |
| • | All conditions satisfied for 5 seconds |
Condition 2:
This condition detects D2, D4, or Rev during an engine start.
| • | No VSS DTC P0502 |
| • | No system voltage DTC P0560 |
| • | The engine speed is less than 100 RPM for 0.3 seconds; then |
| the engine speed is between 100 and 600 RPM for 0.3 seconds; then |
| the engine speed is greater than 600 RPM for 3 seconds. |
| • | The vehicle speed is less than 3 km/h (2 mph). |
| • | The detected gear range is D2, D4, or Rev. |
| • | All conditions satisfied for 3 seconds |
Condition 3:
This condition detects P/N when the vehicle should be in D4.
| • | No TP DTCs P0122 or P0123 |
| • | No VSS DTC P0502 |
| • | The engine speed is less than 2000 RPM. |
| • | The speed ratio is between 0.39 and 0.8 (speed ratio is engine speed divided by transmission output speed). |
| • | The engine vacuum is between 35 and 70 kPa. |
| • | The TCC is locked ON. |
| • | The detected gear range is Park/Neutral. |
| • | All conditions satisfied for 5 seconds |
Action Taken When the DTC Sets
| • | D2 line pressure. |
| • | D4 shift pattern. |
| • | The freeze shift adapts from being updated. |
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
Conditions for Clearing the 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
| • | Refer to the TFP Valve Position Switch Logic Table for the normal range signals and the illegal combinations. |
| • | Inspect the wiring for any poor electrical connections at the PCM. Inspect the wiring 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. |
| • | Refer to the Automatic Transmission Fluid Pressure (TFP) Manual Valve Position Switch Resistance Check or the Functional Test Procedure for further information. |
Gear Position | Range Signal A | Range Signal B | Range Signal C |
|---|---|---|---|
Park | OFF | ON | OFF |
Reverse | ON | ON | OFF |
Neutral | OFF | ON | OFF |
D4 | OFF | ON | ON |
D3 | OFF | OFF | ON |
D2 | OFF | OFF | OFF |
D1 | ON | OFF | OFF |
Illegal | ON | OFF | ON |
Illegal | ON | ON | ON |
Test Description
The numbers below refer to the step numbers on the diagnostic chart.
-
This Step compares the idicated range signal to the manual valve you actually select.
-
This Step verifies that the transmission 20-way connector receives the correct voltage 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 , Section 6E3 | |||||||
2 |
Have you completed the procedure? | -- | Go to 4L60-E Transmission Fluid Checking Procedure | |||||||
Important: Before clearing 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. Does each selected transmission range match the Trans Range displayed on the scan tool? | -- | Go to Diagnostic Aids | ||||||||
Did you measure B+ on all three circuits? | -- | |||||||||
5 | Inspect the circuits that did not indicate B+ for an open or a short to ground. Refer to Electrical Diagnosis, Section 8A. Did you find and correct a problem? | -- | ||||||||
6 | Verify that circuits 1224, 1225, and 1226 are not shorted together. Use a fused jumper to ground on each circuit while monitoring the scan tool TFP Switch A/B/C display. When a range signal circuit is grounded, are any other range signal circuits affected? | -- | ||||||||
7 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming , Section 6 Is the replacement complete? | -- | -- | |||||||
8 | Repair the affected wiring as necessary. Refer to Electrical Diagnosis, Section 8A. Is the repair complete? | -- | -- | |||||||
9 |
Has the test run and passed? | -- | System OK |
