GM Service Manual Online
For 1990-2009 cars only
Table 1: Gear Position and Range Signal Chart
Table 2: DTC P0706

Circuit Description

The transmission range (TR) switch is located on the selector shaft and informs the transmission control module (TCM) of the current selector lever position P-R-N-D-3-2-1.

The selector lever position is transmitted to the TCM in encoded form along 4 lines. The encoding is such that malfunctions in the connecting lead are identified.

The TR switch is located on the selector shaft, which is connected to the selector lever via a pull cable. In addition, the TR switch controls the starter interlock, the reverse lights and the selector lever position indicator on the instrument panel.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC P0706 Transmission Range (TR) Switch Performance

Conditions for Setting the DTC

    • TR switch stuck to closed
    • TR switch wiring harness shortage to ground
    • TR switch wiring harness shortage to power
    • Immediately after the above condition occurs

Action Taken When the DTC Sets

    • The hold lamp will blink.
    • The TCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Failure Records buffer.
    • Adopt Emergency/Substitute mode and constant 4th gear.

Conditions for Clearing the Hold Lamp/DTC

    • The hold lamp will turn OFF when the malfunction has not occurred after 3 ignition cycles.
    • A history DTC will clear after 40 consecutive warm-up cycles without a fault.
    • Using a scan tool can clear history DTCs.

Diagnostic Aids

When DTC P0706 sets, the possible cause of TR switch

Gear Position and Range Signal Chart

Gear Position

L1

L2

L3

L4

P

0

0

12

0

R

0

0

0

12

N

0

12

0

0

D

12

12

12

0

3

12

12

0

12

2

12

0

12

12

1

0

12

12

12

DTC P0706

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Install the scan tool.
  2. Turn the ignition ON, with the engine OFF.
  3. Record then clear the DTCs.
  4. Turn the ignition OFF, then turn the ignition ON, with the engine OFF.
  5. Apply the brakes and select each transaxle range (P, R,N,D,3,2,1), while monitoring scan tool.
  6. Refer to the Gear Position and Range Signal Chart.

Does each selected transaxle range match scan tool and signal range chart?

--

Go to Step 3

Go to Diagnostic Aids

3

Inspect the F2 for an open.

Was a problem found?

--

Go to Step 4

Go to Step 5

4

Replace the fuse, as necessary.

Is the action complete?

--

System OK

--

5

Inspect the transmission range (TR) switch. Refer to Diagnostic Aids.

Was the problem found?

--

Go to Step 6

Go to Step 7

6

Replace the TR switch. Refer to Park/Neutral Position Switch Replacement .

Is the action complete?

--

System OK

--

7

  1. Disconnect the TR switch connector and the transmission control module (TCM) connector.
  2. Measure the resistance between terminal 3 of the TR switch and terminal C1 of the TCM connector.
  3. Measure the resistance between terminal 2 of the TR switch and terminal B15 of the TCM connector.
  4. Measure the resistance between terminal 4 of the TR switch and terminal B6 of the TCM connector.
  5. Measure the resistance between terminal 5 of the TR switch and terminal B11 of the TCM connector.

Is the resistance approximately equal to the specified value?

0 ohms

Go to Step 9

Go to Step 8

8

Repair the malfunctioning terminals, as necessary.

Is the action complete?

--

System OK

--

9

  1. Turn the ignition ON, with the engine OFF.
  2. Measure the voltage of terminal 3.
  3. Measure the voltage of terminal 2.
  4. Measure the voltage of terminal 4.
  5. Measure the voltage of terminal 5.

Is the voltage within the specified value?

11-14 V

Go to Step 10

Go to Step 11

10

Repair the malfunctioning terminals, as necessary.

Is the action complete?

--

System OK

--

11

Replace the TCM. Refer to Transmission Control Module Replacement .

Is the action complete?

--

Go to Step 12

--

12

  1. After the repair, use a scan tool "clear info" function.
  2. Road test the vehicle.
  3. Review the DTC info.

Has the last test failed or is the current DTC displayed?

--

Go to Step 2

System OK