P0705
DTC P0705 (4.2L)
Circuit Description
The transmission range (TR) switch is part of the park/neutral position and back-up lamp switch assembly and is externally mounted on the transmission manual shaft. The TR switch is a multi-signal switch. The powertrain control module (PCM)/transmission control module (TCM) supplies ignition voltage to the TR switch on 4 signal circuits, A, B, C, and P. Each gear selector lever position grounds one or more of the switch circuits. In order to determine the gear range selected by the driver, the PCM/TCM compares the voltage combinations on the signal circuits to a look up table stored in the PCM/TCM memory. PCM/TCM detects the selected gear range by the state change of the switch input. Refer to table Transmission Range Switch Logic.
Switch input to the PCM/TCM is represented on the scan tool as HI and LOW. HI indicates an ignition voltage signal. LOW indicates a zero voltage signal. The 4 parameters represent transmission range switch signal A, B, C and Parity.
When the PCM/TCM detects an invalid TR switch signal combination, then DTC P0705 sets. DTC P0705 is a type C DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0705 Transmission Range (TR) Switch Circuit
Conditions for Running the DTC
- The system voltage is 8-18 volts.
- The engine run time is greater than 5 seconds.
Conditions for Setting the DTC
The combination of TR switch signals are invalid for 10 seconds. Refer to the table Transmission Range Switch Logic.
Action Taken When the DTC Sets
- The PCM/TCM does not illuminate the malfunction indicator lamp (MIL).
- The PCM/TCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM/TCM stores this information as Failure Records.
- The PCM/TCM stores DTC P0705 in PCM/TCM memory.
Conditions for Clearing the DTC
- A scan tool can clear the DTC.
- The PCM/TCM clears the DTC from PCM/TCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring.
- The PCM/TCM cancels the DTC default actions when the fault no longer exists and the DTC passes.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
5. By disconnecting the TR switch, the ground path of all TR switch circuits would be removed and the PCM/TCM would recognize all circuits as open. The scan tool will display HI for all range signals.
6. This step tests TR switch wiring for an open or the lack of the signal voltage from the PCM/TCM.
7. This step tests TR switch wiring and the PCM/TCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal A should change to LOW.
8. This step tests TR switch wiring and the PCM/TCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal B should change to LOW.
9. This step tests TR switch wiring and the PCM/TCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal C should change to LOW.
