GM Service Manual Online
For 1990-2009 cars only

Object Number: 882387  Size: MF
Master Electrical Component List
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice

Circuit Description

The input shaft speed (ISS) sensor is a permanent magnet generator. The ISS sensor is mounted inside the transmission, under the control valve body cover. The sensor faces the input shaft speed sensor reluctor ring assembly. As the reluctor ring assembly rotates, an AC voltage is induced and transmitted to the transmission control module (TCM). The AC voltage level and the number of pulses increase as the speed of the reluctor ring assembly increases. The TCM converts the AC voltage into a digital signal. The TCM uses the input speed signal to help determine line pressure, transmission ratio control patterns and TCC apply pressure and timing.

If the TCM detects no input shaft speed when there is vehicle speed in a drive gear range, DTC P0717 sets. DTC P0717 is a type A DTC.

Conditions for Running the DTC

    • No transmission range switch DTCs P0705, P1756, or P1758.
    • No OSS DTCs P0722 or P0723.
    • No engine torque DTC P1779.
    • The engine speed is greater than 500 RPM for 5 seconds.
    • The selected range is not PARK or NEUTRAL.
    • The engine torque is between 30-300 N·m (22-221 lb ft).
    • The transmission output shaft speed is 400 RPM or greater.

Conditions for Setting the DTC

The transmission input shaft speed is 100 RPM or less for 5 seconds.

Action Taken When the DTC Sets

    • The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
    • The TCM moves the speed ratio towards a target ratio and then freezes ratio changes.
    • The TCM discontinues use of the closed loop ratio control algorithm. This causes the speed ratio to be defaulted and possibly not accurate. The resulting open loop control may or may not provide optimum ratio performance.
    • The TCM commands maximum pressure to the input clutch.
    • The TCM calculates input shaft speed from the output shaft speed sensor and the commanded speed ratio.
    • The TCM commands a line pressure increase for all operating conditions.
    • The TCM freezes garage shift transmission adaptive functions.
    • The TCM freezes main line pressure transmission adaptive functions.
    • The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
    • The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
    • The TCM stores DTC P0717 in TCM history.

Conditions for Clearing the MIL/DTC

    • The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
    • A scan tool can clear the MIL/DTC.
    • The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
    • The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids

    • Ensure the ISS is properly installed in the transmission.
    • Inspect the connectors at the TCM, the transmission, and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The resistance measurement will not change if either the ISS high signal circuit or the ISS low signal circuit, but not both, is shorted to ground. The vehicle speed detector in the TCM and the ISS are matched in such a way that an open or a short to ground in the ISS low signal circuit will not usually cause a loss of speed signal or a DTC P0717 to set.

  2. This step isolates the short between the ISS and the wiring.

  3. Refer to the latest procedures for TCM reprogramming.

Step

Action

Values

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 - 2.2L (L61)

2

  1. Install a scan tool.
  2. Turn ON the ignition with the engine OFF.
  3. Important: 

       • Before clearing the DTC, use the scan tool in order to record the ECM Freeze Frame and the TCM Failure Records. Using the Clear Eng./Trans. DTC Info function erases the Freeze Frame and Failure Records from the ECM and the TCM.
       • Using the Clear Eng./Trans. DTC Info function erases stored DTCs in both the ECM and TCM.

  4. Record the DTC Freeze Frame and Failure Records.
  5. Clear the DTC.
  6. Start the engine.
  7. Operate the vehicle as described in Conditions for Running the DTC.
  8. Select specific DTC.
  9. Enter P0717.

Has the test run and passed?

--

Go to Intermittent Conditions in Engine Controls - 2.2L (L61)

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the TCM C2 connector.
  3. Using the DMM and the J-35616 Connector Test Adapter Kit, measure the resistance between the ISS high signal and the ISS low signal circuits at the TCM connector.

Is the resistance within the specified range?

1,000-2,000 ohms

Go to Step 5

Go to Step 4

4

Test the ISS high signal circuit and ISS low signal circuit for the following conditions:

    • An open circuit or high resistance condition
    • ISS high signal and ISS low signal circuits shorted together

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 13

Go to Step 9

5

Measure the resistance between the ISS high signal circuit at the TCM connector and ground.

Is the resistance greater than the specified value?

50K ohms

Go to Step 8

Go to Step 6

6

  1. Leave the DMM connected between the ISS high signal circuit and ground.
  2. Disconnect the AT inline 20-way connector.
  3. Measure the resistance.

Is the resistance greater than the specified value?

50K ohms

Go to Step 9

Go to Step 7

7

Repair the short to ground in the ISS high signal circuit. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 13

--

8

  1. Connect the DMM between the ISS high signal and the ISS low signal circuits at the TCM connector.
  2. Place the transmission in PARK.
  3. Start the engine.

Is the AC voltage equal to or greater than the specified value?

0.5 V

Go to Step 9

Go to Step 10

9

Test for continuity between the ISS high signal circuit of the TCM C2 64-way connector and all other terminals except the ISS low signal circuit. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems.

Did you find and correct a condition?

--

Go to Step 13

Go to Step 12

10

  1. Remove the ISS. Refer to Input and Output Speed Sensor Replacement .
  2. Inspect the ISS and the ISS reluctor assembly for the following conditions:
  3. • Poor connections at leadframe
    • ISS damage
    • ISS reluctor assembly damage
    • Excessive air gap between the input shaft speed sensor reluctor ring assembly (521) and the ISS
    • Incorrect alignment between the ISS and the input shaft speed sensor reluctor ring assembly (521)
  4. Repair or replace any of the above items as necessary.

Did you find and correct a condition?

--

Go to Step 13

Go to Step 11

11

Replace the ISS. Refer to Input and Output Speed Sensor Replacement .

Did you complete the replacement?

--

Go to Step 13

--

12

Replace the TCM. Refer to Transmission Control Module Replacement .

Is the action complete?

--

Go to Step 13

--

13

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Start and idle the engine.
  4. Observe Transmission ISS on the scan tool. Input speed must be 100 RPM or greater for 5 seconds.
  5. Select Specific DTC.
  6. Enter DTC P0717.

Has the test run and passed?

--

Go to Step 14

Go to Step 2

14

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 - 2.2L (L61)

System OK