P1527

Transaxle Range Switch Valid Input Combinations:

Circuit Description

This vehicle uses an electronic gear indicator display. There are four inputs which are switches to ground that each have a unique switch pattern. All four of these inputs are housed in the PNP switch and operate together as the Transaxle Range Switch. The PCM uses the combination of the switch patterns to determine the gear selected by the driver. This information is then sent by serial data to the Instrument Panel Cluster (IPC) for gear indicator display. When the Conditions for Running the DTC are true this test compares the gear indicated by the Transaxle Range Switch to the gear selected from the Transmission Fluid Pressure Manual Valve Position Switch (TFP switch). If the gear indicated is not the same for both, this DTC is set.

Conditions for Running the DTC

^ Engine running continuously for 5 seconds.
^ Ignition voltage is between 10 and 16 volts.
^ Transaxle Range switch does not indicate an illegal position.
^ Transmission Fluid Pressure Manual Valve Position Switch (TFP switch) does not indicate an illegal position.
^ DTC P1810 has ran and passed.

Conditions for Setting the DTC

The Transaxle Range switch and the Transmission Fluid Pressure Manual Valve Position Switch (TFP switch) indicate different gears for at least 7.8 seconds.

Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will not illuminate.
^ No message will be displayed.

Conditions for Clearing the MIL/DTC

^ A History DTC will clear after forty consecutive warm-up cycles with no failures of any non-emission related diagnostic test.
^ A Last Test Failed (current) DTC will clear when the diagnostic runs and does not fail.
^ Use a scan tool to clear DTCs.
^ Interrupting PCM battery voltage may or may not clear DTCs. This practice is not recommended.

Diagnostic Aids

^ The modes (circuits) are displayed in order A/B/C/P.
^ L indicates the circuit low (switched / shorted to ground).
^ H indicates the circuit is high (open).
^ If the DTC sets and the PRNDL on the IPC is flashing while driving or when the driver in not moving the gear selector lever, record the transaxle range switch input and compare the values to the table. For example, if the vehicle was operating in overdrive when the PRNDL on the IPC flashed and the input read High, Low, High, High, check for an intermittent open in circuit 773.
^ Manipulate related wiring and connectors while observing the transaxle range switch input. If an intermittent is induced, the digit corresponding to the circuit will change.
^ Use the Failure Records data to help determine which switch was reading incorrectly. If the DTC set and the pressure switch indicated D1 and the select lever switch indicated P/N and the engine sensors (MAP, TP, MAF etc.) appear to indicate the vehicle was in Park or Neutral then check the pressure switch/circuits for an intermittent fault.

Depending on the Scan Tool used, the transmission fluid pressure switch parameter and the gear select lever parameter may have two different titles. For example: when using a Tech 1 on a 1996 vehicle the gear select lever parameter would be named Sel. Lever Sw. and Sel. Lever Sw. A/B/C/P. The same vehicle and parameter using a Tech 2 would be named Transmission Range and T R Switch A/B/C/P. These same parameters may also call the state of the circuit differently. For example: the Tech 1 may indicate ON for an open circuit while the Tech 2 would indicate High for an open circuit. Proper verification of the parameter being observed can be indicated by the inability of the transmission fluid pressure switch to indicate any gear other than Drive 2 when the vehicle is not running (no pressure available).

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. The adjustment procedures must be done before diagnosis of the system. This step does a comparison of both the transaxle range switch and the transaxle pressure switch (TFP switch). If both displays match in all gear selections then the fault is not present or may have been repaired when the adjustment procedures were performed.
3. The engine must be running in order to obtain gear indications from the TFP switch.
If TFP Switch doesn't match the gear selected then the transaxle pressure switches are at fault.
4. Checking if the ground circuit to the switch may be at fault.
5. If a circuit stays High or Low all the time, that circuit or switch is open or shorted to ground.
17. A few conditions could occur in the Transmission Fluid Pressure Manual Valve Position Switch and circuits which may not set a DTC P1810. Only one of these faults could be a circuit only or PCM fault.