GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The Transmission Range Switch attaches externally to the left side of the 4L30-E transmission on the gear selector shaft. The Transmission Range Switch informs the TCM and the console gear position indicator which gear the driver selects.

The ignition voltage is supplied to the switch on terminal D. Depending on the selector lever position, this ignition voltage connects to the various combinations of terminals A, B, C, and G of the Transmission Range Switch. The TCM decodes these combinations in order to determine the gear position. When the TCM detects Park or Neutral with throttle position and engine speed for a period of time or the TCM detects Reverse with high transmission output speed, then DTC P0706 will set. DTC P0706 is a type D DTC.

Conditions for Running the DTC

Condition 1:

For Position N or P:

    • The engine speed is greater than 500 RPM but less than 3008 RPM.
    • The throttle position is greater than 34 percent.
    • DTC P0120 is not set.

Condition 2:

For Position R:

The transmission output speed is greater than 8160 RPM.

Conditions for Setting the DTC

Condition 1:

Position N or P is detected.

Condition 2:

Position R is detected.

Action Taken When the DTC Sets

    • The ECM records the operating conditions in the Failure Records at the time of the DTC request from the TCM.
    • The TCM memory stores the DTC at the time of the first failure.

Conditions for Clearing the DTC

    • A History DTC clears after forty consecutive warm-up cycles, if no failures are present by this diagnostic or any other emission related diagnostic.
    • The scan tool clears the DTC.

Diagnostic Aids

If the Manual Shaft Shift Position Switch is electrically faulty, P0705 will set. If P0705 is set with P0706, diagnose and repair P0705 first.

Test Description

The numbers below refer to the step numbers on the Diagnostic Table.

  1. The Scan Tool display should match the selector lever position at each detent. If you have to move the lever slightly within a position to get the right indication on the Scan Tool , the Transmission Range Switch adjustment should be checked. Refer to Manual Shift Shaft Position Switch Replacement .

DTC P0706 - Transmission Range Switch Performance

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to On-Board Diagnostic System Check

2

  1. Install a Scan Tool .
  2. Turn ON the ignition, with the engine OFF.
  3. Select the transmission data display.
  4. With the Scan Tool , observe the Man. Shft. Posn. Sw. while selecting each transmission range: P, R, N, D, 3, 2, 1.

Does each selected transmission range match the scan tool Man. Shft. Posn. Sw. display?

--

Go to Diagnostic Aids

Go to Step 3

3

Inspect the Manual Shaft Shift Position Switch for:

    • Loose or missing mounting hardware
    • Switch collar slipping around the transmission manual shaft
    • Damage
    • Improper adjustment
    • Loose or damaged linkage

Did you find and correct the condition?

--

Go to Step 5

Go to Step 4

4

Replace the Manual Shaft Shift Position Switch.

Refer to Manual Shift Shaft Position Switch Replacement .

Did you complete the replacement?

--

Go to Step 5

--

5

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. • Drive the vehicle in D range with a throttle position greater than 34%.
    • Ensure that the engine RPM is greater than 3008 after 3.8 seconds.
    • Ensure that the transmission output speed does not exceed 8160 RPM.

Did DTC P0706 reset?

--

Go to Step 1

System OK