P0705
DTC P0705
Circuit Description
The transmission on this vehicle has a park neutral position (PNP) and back-up switch. This switch incorporates a transmission range selector switch. There are 4 inputs, PRND A, B, C, P, which are switches to ground. The 4 switches have an unique switch pattern. The powertrain control module (PCM) and the Alternative Fuels ECM use the combination of the switch patterns in order to determine the gear selected by the driver.
This diagnostic monitors the 4 inputs in order to determine what gear position the transmission is in. When the Alternative Fuels ECM detects that an illegal range has occurred, this DTC sets.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
* The transmission range select lever switch indicates an illegal position.
* The Alternative Fuels ECM detects an illegal range for 30 seconds.
Action Taken When the DTC Sets
* The Alternative Fuels ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
* The Alternative Fuels ECM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the Alternative Fuels ECM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the Alternative Fuels ECM records the operating conditions at the time of the failure. The Alternative Fuels ECM writes the conditions to the Freeze Frame and updates the Failure Records.
Conditions for Clearing the MIL/DTC
* The Alternative Fuels ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
* A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
* A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
* Use a scan tool in order to clear the MIL and the DTC.
Diagnostic Aids
This DTC will set if the gear shift cable, or PNP switch is not adjusted properly. Also, if the gear shift lever is held between gears, this DTC will set.
Refer toAutomatic Transmission Range Selector Cable Adjustment andPark/Neutral Position Switch Adjustment in Automatic Transmission-4L80-E in the C/K Pickup Service Manual.
The table below is the normal state that each gear range should indicate. LOW indicates the circuit is low, switched or shorted to a ground. HI indicates the circuit is high or open. Another parameter to display is the TR Sw. A/B/C/P range. This parameter displays the current gear range the transmission is in. When there is an invalid gear range, the parameter indicates Invalid.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines if the condition is present.
4. This step determines if the condition affects the PCM. If the Transmission Data display matches the selected transmission range, the condition only affects the Alternative Fuels ECM.
5. This step determines if the ground circuit of the TR switch is the cause of the condition. If the data displays HI for all of the circuits, test the ground circuit for an open.
6. When the TR switch is disconnected, all of the data parameters should display HI.
7. This step tests TR switch wiring for an open or the lack of the signal voltage from the PCM.
8. This step tests TR switch wiring and the PCM by providing a ground path through a fused jumper wire. When grounded, the scan tool range signal should change to LOW.
9. This step tests for an open circuit between the Alternative Fuels ECM and the splice.
10. This step determines if the Alternative Fuels ECM is the cause of the condition. If the data display switches from LOW to HI when the Alternative Fuels ECM is disconnected, the module is causing the short to ground.
