GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The turbine sensor is a permanent magnet with a coil of wire wound around it. The turbine sensor mounts in the transmission side cover facing the reluctor wheel of the input shaft. As the turbine shaft drives the reluctor wheel, an AC signal is inducted in the input speed sensor. Higher vehicle speed induce a higher frequency and voltage at the sensor.

There is a fixed air gap between the sensor and the teeth on the sensor reluctor wheel. The turbine sensor input is used by the TCM in order to control line pressure, TCC apply and release and transmission shift patterns. This sensor is also used to calculate the appropriate gear ratios and TCC slippage.

The diagnostic indicates stuck, erratic, or intermittent conditions in the system.

If the TCM detects an unrealistically large change in the turbine sensor high signal in a short period of time, then DTC 15 sets.

Conditions for Running the DTC

    • Road test the vehicle. Refer to Road Test .
    • Transmission oil temperature is between 0°C (32°F) and 120°C (248°F)

Conditions for Setting the DTC

No input signal

Action Taken When the DTC Sets

    • The TCM illuminates the A/T warning lamp when the diagnostic runs and fails.
    • Line pressure control is set to full throttle.

Conditions for Clearing the MIL/DTC

The TCM turns OFF the A/T warning when the diagnostic runs and does not fail.

DTC 15

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission

2

  1. Ignition OFF.
  2. Disconnect the turbine sensor connector.
  3. Using a DMM, measure resistance at the turbine sensor connector between terminals C1 and C2.

Is the resistance within the specified value?

500-580ohms

Go to Step 3

Go to Step 6

3

  1. Disconnect the TCM.
  2. Using a DMM, measure resistance at the turbine sensor harness connector between terminals C1 and C2 and ground.
  3. Start the engine.

Is the resistance less than the specified value?

0.3ohms

Go to Step 7

Go to Step 4

4

Using a DMM, measure voltage turbine sensor harness connector between terminals C1 and C2 and ground.

Is the voltage greater than the specified value?

0 volts

Go to Step 8

Go to Step 5

5

  1. Connect a jumper between TCM connector terminals 8 and 9.
  2. Using a DMM, measure resistance at the turbine sensor harness connector between terminals C1 and C2 and ground.

Is the resistance greater than the specified value?

0.3ohms

Go to Step 9

Go to Step 10

6

Replace the turbine sensor.

Did you complete the replacement?

--

Go to Step 11

--

7

Repair the turbine sensor circuits for a short to ground.

Did you complete the repair?

--

Go to Step 11

--

8

Repair the turbine sensor circuits for a short to voltage.

Did you complete the repair?

--

Go to Step 11

--

9

Repair the turbine sensor circuits for an open or high resistance.

Did you complete the repair?

--

Go to Step 11

--

10

Replace the TCM. Refer to Transmission Control Module Replacement .

Did you complete the replacement?

--

Go to Step 11

--

11

  1. Clear the DTCs. Refer to Clearing Transmission Diagnostic Trouble Codes .
  2. Start the engine.
  3. Operate the vehicle within Conditions for Running the DTC.
  4. Did the DTC reset?

--

Go to Step 2

System OK