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

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 connection 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.

Conditions for Setting the DTC

    • The TR switch is stuck to closed.
    • The TR switch wiring harness is shorted to ground.
    • The TR switch wiring harness is shorted to power.

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 the 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

0

0

12

12

1

12

12

12

12

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check-Automatic Transmission?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

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

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

--

Go to Step 3

Go to Diagnostic Aids

3

Inspect the F10 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 a 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 within the specified value?

0ohms

Go to Step 9

Go to Step 8

8

Repair the malfunction terminals as necessary.

Is the action complete?

--

System OK

--

9

  1. Turn ON the ignition, 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.

Iis the voltage within the specified range?

11-14 V

Go to Step 10

Go to Step 11

10

Repair the malfunction terminals as necessary.

Is the action complete?

--

System OK

--

11

Replace the TCM. Refer to Transmission Control Module Replacement

Is the replacement complete?

--

Go to Step 12

--

12

  1. After the repair, use the scan tool Clear Info function and road test the vehicle.
  2. Review the DTC Info.

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

--

Go to Step 2

System OK