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) 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 compares the voltage combinations on the signal circuits to a look up table stored in the PCM memory. PCM detects the selected gear range by the state change of the switch input. Refer to Transmission Range Switch Logic table.
Switch input to the PCM 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 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. |
| • | The engine speed is greater than 500 RPM. |
Conditions for Setting the DTC
The combination of TR switch signals are invalid for 60 seconds. Refer to the Transmission Range Switch Logic table.
Action Taken When the DTC Sets
| • | The PCM does not illuminate the malfunction indicator lamp (MIL). |
| • | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records. |
| • | The PCM stores DTC P0705 in PCM memory. |
Conditions for Clearing the DTC
| • | A scan tool can clear the DTC. |
| • | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-emission-related diagnostic fault occurring. |
| • | The PCM 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.
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By disconnecting the TR switch, the ground path of all TR switch circuits would be removed and the PCM would recognize all circuits as open. The scan tool will display HI for all range signals.
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This step tests TR switch wiring for an open or the lack of the signal voltage from the PCM.
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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 A should change to LOW.
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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 B should change to LOW.
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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 C should change to LOW.
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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 states should change to LOW.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Does each selected transmission range match the scan tool TR Sw. display? | -- | Go to Step 3 | Go to Step 4 |
3 | Observe the instrument panel cluster (IPC) gear range display while selecting each transmission range: P, R, N, D4, D3, D2, D1. Does each selected transmission range match the IPC display? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 17 |
4 | With the scan tool, observe the TR Sw. A/B/C/P display. Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | -- | Go to Step 14 | Go to Step 5 |
Does the scan tool TR Sw. A/B/C/P parameter indicate HI for all range signal states? | -- | Go to Step 6 | Go to Step 11 | |
Does the voltage measure within the specified value at all four circuits? | 10-12 V | Go to Step 7 | Go to Step 12 | |
Connect a fused jumper wire from the TR switch connector, signal circuit A, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit A is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 13 | Go to Step 8 | |
Connect a fused jumper wire from the TR switch connector, signal circuit B, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit B is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 13 | Go to Step 9 | |
Connect a fused jumper wire from the TR switch connector, signal circuit C, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit C is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 13 | Go to Step 10 | |
Connect a fused jumper wire from the TR switch connector, signal circuit P, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When signal circuit P is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 13 | Go to Step 14 | |
11 | Test the signal circuits of the TR switch that did not indicate HI for a short to ground. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 16 |
12 | Test the signal circuits of the TR switch that did not indicate proper voltage for an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 16 |
13 | Test the affected signal circuits of the TR switch for a shorted together condition. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 16 |
14 | Test the ground circuit of the TR switch for an open. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 15 |
15 | Replace the TR switch, this switch is part of the park/neutral position switch. Refer to Park/Neutral Position and Backup Lamp Switch Replacement. Did you complete the replacement? | -- | Go to Step 18 | -- |
16 | Replace the powertrain control module (PCM). Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 18 | -- |
17 | Replace the IPC. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | -- | Go to Step 18 | Go to Step 3 |
18 |
Does each selected transmission range match the scan tool TR Sw. display? | -- | Go to Step 19 | Go to Step 3 |
19 | With the scan tool, observe the stored information, capture info, and DTC Info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |
