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 four 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 .
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 four parameters represent transmission range switch signal A, B, C and Parity.
DTC P0706 sets if the PCM detects vehicle speed in PARK or NEUTRAL range. DTC P0706 is a type C DTC.
Conditions for Running the DTC
| • | No TPS DTCs P0121, P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No incorrect gear ratio DTC P0730. |
| • | Ignition voltage is 6-18 volts. |
| • | The engine is running for greater than 60 seconds. |
| • | The commanded gear is 3rd or 4th. |
| • | The throttle angle is 5 percent or greater. |
| • | The engine torque is greater than 68 N·m (50 lb ft). |
| • | The vehicle speed is 32 km/h (20 mph) or greater. |
| • | The PTO mode is not active. |
Conditions for Setting the DTC
Condition 1
The PCM detects DRIVE or REVERSE at vehicle start-up.
Condition 2
The Conditions for Running the DTC are met and the PCM detects PARK or NEUTRAL.
Action Taken When the DTC Sets
| • | The PCM will use TFP Switch to determine gear range. |
| • | 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 P0706 in PCM history. |
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 transmission range 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.
Step | Action | Value(s) | Yes | No | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 4.8L, 5.3L, and 6.0L | ||||||||||||||
2 |
Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Failure Records from the PCM. Does each selected transmission range match the scan tool TR Sw. display? | -- | Go to Intermittent Conditions in Engine Controls - 4.8L, 5.3L, and 6.0L | Go to Step 3 | ||||||||||||||
3 |
Did you find and correct a condition? | -- | Go to Step 16 | Go to Step 4 | ||||||||||||||
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 13 | 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 10 | |||||||||||||||
Does the voltage measure within the specified value at all four terminals? | 10-12 V | Go to Step 7 | Go to Step 11 | |||||||||||||||
Connect a fused jumper wire from terminal A of the TR switch 4-way connector, signal A circuit to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal A circuit (CKT 771) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 12 | Go to Step 8 | |||||||||||||||
Connect a fused jumper wire from terminal D of the TR switch 4-way connector, signal B circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal B circuit (CKT 772) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 12 | Go to Step 9 | |||||||||||||||
Connect a fused jumper wire from terminal B of the TR switch 4-way connector, signal C circuit, to ground while monitoring the scan tool TR Sw. A/B/C/P parameter. When the signal C circuit (CKT 773) is grounded, do any other signal circuits indicate LOW? | -- | Go to Step 12 | Go to Step 14 | |||||||||||||||
10 | Test the signal circuits (CKTs 771, 772, 773 and 776) of the TR switch that did not indicate HI for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||||||||||
11 | Test the signal circuits (CKTs 771, 772, 773 and 776) of the TR switch that did not indicate proper voltage for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||||||||||
12 | Test the affected signal circuits of the TR switch for a shorted together condition. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 15 | ||||||||||||||
13 | Test the ground circuit (CKT 451) of the TR switch for an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 14 | ||||||||||||||
14 | Replace the TR switch. The TR switch is part of the park/neutral position (PNP) switch. Refer to Park/Neutral Position Switch Replacement . Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||||||||||
15 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.8L, 5.3L, and 6.0L. Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||||||||||
16 | Perform the following procedures in order to verify the repair:
Has the test run and passed? | -- | Go to Step 17 | Go to Step 2 | ||||||||||||||
17 | 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? | -- | Go to Diagnostic Trouble Code (DTC) List in Engine Controls - 4.8L, 5.3L, and 6.0L | System OK |
