P1810

DIAGNOSTIC TROUBLE CODE (DTC) P1810 TRANSAXLE RANGE (TR) SELECTION SWITCH MALFUNCTION





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 are used for determining gear range selection. The sixth switch is a normally closed switch and is used to detect TCC release fluid pressure. The TFP Val. Position Sw. also contains a Trans Fluid Temperature (TFT) sensor. These components are combined into one unit and mounted on the valve body.
The Powertrain Control Module (PCM) provides battery voltage on each range signal. By grounding one or more of these switches with fluid pressure from the manual shift valve, the PCM detects what gear. range has been selected. When the transmission electrical connector is disconnected 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.
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.


Conditions For Setting The DTC
This DTC will set under any one of the following three conditions:


Condition 1
- Engine running.
- Gear range is illegal for five seconds.

Condition 2
- No VSS DTC(s) P0722 or P0723.
- Engine speed is in transition from O to more than 500 rpm.
- TFP Val. Position Sw. indicates D2, D4 or Reverse at engine start-up.
- The system voltage is 10-16 volts.
- The vehicle speed is less than 2 mph (3 km/h).
- All the above conditions are met for 2 seconds.


Condition 3
- Engine running.
- No TP DTC P1791.
- No VSS DTCs P0722 or P0723.
- No Input Speed Sensor DTCs P0716 or P0717.
- MAP is 10-105 kPa.
- No shift solenoid DTC(s) P0751, P0753, P0756 or P0758.
- Vehicle speed is equal to or greater than 5 mph (8 km/h).
- TP is greater than 10%.
- Engine torque is greater than 115 inch lbs. (13 Nm ).
And any one of the following three conditions occur:
- TR Switch indicates P (Park)/N (Neutral) when gear ratio is less than 0.72 (4th gear) for 5 seconds.
- TR Switch indicates Reverse when ratio is greater than 2.23 or less than 2.02 for 5 seconds.
- TR Switch indicates D, 3, 2, or 1 when ratio indicates Reverse for 5 seconds.


Action Taken When The DTC Sets
- The PCM will illuminate the Malfunction Indicator Lamp (MIL) after two consecutive trips with a failure reported.
- Freeze shift adapts from being updated.
- PCM assumes D4 shift pattern.
- Elevate a line pressure.
- PCM inhibits TCC engagement.
- DTC P1810 will be stored in PCM memory.


Conditions For Clearing the DTC
Condition 1
- Engine running.
- TR Switch does not detect an illegal range for 5 seconds, three consecutive ignition cycles.


Condition 2
- When the following is true for three consecutive ignition cycles.
- System voltage is 10-16 volts.
- No VSS DTCs P0722 or P0723.
- Vehicle speed less than 11 km/h (7 mph).
- TFP Val. Position Sw. indicates park or neutral for 3 seconds.

Condition 3
- After three consecutive ignition cycles when the following is true:
- TR Switch indicates P (Park) or N (Neutral) when ratio is greater than 0.72 for 5 seconds.
- TR Switch indicates Reverse when ratio is between 2.02 and 2.23 for 5 seconds.
- TR Switch indicates D or 3 or 2 or 1 when the ratio is less than 2.02 or greater than 2.23 for 5 seconds.
- History DTC(s) can be cleared by using a Scan Tool.


Diagnostic Aids
- A pressure regulator problem could possibly set DTC P1810.
- Inspect the wiring for poor electrical connections at the PCM and at the transmission 20-way connector. Look for possible bent, backed out, deformed or damaged terminals. Check for weak terminal tension as well. Also check for chafed wires that could short to bare metal or other wiring. Inspect for broken wire inside the insulation.
- If diagnosing for a possible intermittent short or open condition, move or massage the wiring harness while observing test equipment for a change.


Test Description
The numbers below refer to the step numbers on the diagnostic chart.











4. This step tests the PCM's ability to recognize an open circuit on signal "A", "B" and "C" ranges.












DIAGNOSTIC TROUBLE CODE (DTC) P1810 TRANSAXLE RANGE PER) SELECTION SWITCH MALFUNCTION