GM Service Manual Online
For 1990-2009 cars only

Object Number: 15697  Size: MF
Automatic Transmission Components
TFP Val. Position Sw., TFT Sensor, and A/T ISS Sensor
Handling ESD Sensitive Parts Notice
OBD II Symbol Description Notice

Circuit Description

The Automatic Transmission Input(Shaft) Speed (A/T ISS) sensor is a permanent magnet with a coil of wire wound around it. The A/T ISS sensor mounts in the transmission case facing the drive sprocket of the input shaft. An air gap of 0.045-0.109 in. between the sensor and the drive sprocket must be maintained so that an accurate AC voltage can be transmitted. Sensor voltage varies from 0.5 volts AC at 100 RPM to more than 100 volts at 8000 RPM. The A/T ISS sensor has a resistance value of 1300-1950 ohms.

When the PCM detects a low input speed while the vehicle and engine speeds are high, then DTC P0717 sets. DTC P0717 is a Type A DTC.

Conditions for Setting the DTC

    • No TP DTCs P0121, P0122 or P0123 are set.
    • No VSS DTCs P0502 or P0503 are set.
    • No TFP Val. Position Sw. DTC P1810 is set.
    • The engine is running for more than 5 seconds.
    • The transmission is not in Park or Neutral.
    • The vehicle speed is greater than 16 km/h (10 mph).
    • The input(shaft) speed is less than 50 RPM for 2 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the Malfunction Indicator Lamp (MIL).
    • SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the Driver Information Center (DIC).
    • The PCM commands default line pressure.
    • The PCM inhibits Torque Converter Clutch.
    • The PCM inhibits torque management.
    • The PCM disables steady state adapts.
    • The PCM disables upshift adapts.
    • The PCM disables garage shift adapts.
    • The PCM inhibits garage shift pressure calculations.
    • The PCM calculates input(shaft) speed from vehicle speed and commanded gear.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
    • A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
    • The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids

    • Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Inspect the wiring for poor electrical connections at the A/T ISS sensor 2-way connector. Look for the following conditions:
       - A bent terminal
       - A backed out terminal
       - A damaged terminal
       - Poor terminal tension
       - A chafed wire
    • When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
    • Inspect the transmission 20-way connector for transmission fluid.

Test Description

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

  1. This Step ensures that you perform the Powertrain On-Board Diagnostic System Check.

  2. This Step verifies that the DTC is set, and that Input (Shaft) speed RPM is displayed on the scan tool.

  3. This Step inspects circuit 1230 and circuit 1231 for an AC voltage. Use the J 35616-A Test Connector Adapter Kit, so as not to damage the terminals.

  4. This Step inspects circuit 1230 for a voltage of 300 mV or greater.

  5. This Step inspects circuit 1230 for an open or short to ground, if the voltmeter displayed less than 300 mV.

  6. This Step verifies that circuit 1231 is not open.

  7. This Step inspects circuit 1231 for an open, if the voltmeter displayed less than 300 mV.

  8. This Step measures the resistance value of the Automatic Transmission Input (Shaft) Speed sensor and circuitry. The ohmmeter must display a value between 1300-1950 ohms. Use the J 35616-A Test Connector Adapter Kit, so as not to damage the terminals.

  9. This Step inspects circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for an open, if the resistance value is greater than 1950 ohms. You must replace the transmission harness, if you find an open in the harness.

  10. This Step inspects circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for a short together, if the resistance value is less than 1300 ohms. You must replace the transmission harness, if you find a short together in the harness.

  11. This Step tests the 1231 and 1231 circuits for a short to ground if the resistance value is less than 100 ohms. You must replace the transmission harness, if you find a short to ground in the harness.

  12. This Step replaces the A/T ISS Sensor after you verify that the Engine Wiring Harness and the Automatic Transmission Wiring Harness are functioning normally.

  13. This Step replaces the PCM after you have inspected the components and circuitry.

DTC P0717 Automatic Transmission Input (Shaft) Speed Sensor Circuit No. Signal

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to A Powertrain On Board Diagnostic (OBD) System Check

2

  1. Install the scan tool (tech 1) .
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.

  4. Record the DTC Freeze Frame and Failure Records.
  5. Select Trans. ISS on the scan tool.
  6. Start the engine.

Does the scan tool display an Automatic Transmission input speed greater than the specified value?

100 RPM

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn the ignition OFF.
  2. Disconnect PCM connector C1.
  3. Connect a voltmeter from PCM connector terminal 5 to terminal 6.
  4. Select AC volts.
  5. Crank the engine.

Does the voltmeter display an AC voltage greater than the specified value?

0.5V AC

Go to Step 11

Go to Step 4

4

  1. Turn the ignition OFF.
  2. Reconnect PCM connector C1.
  3. Disconnect the transmission 20-way connector.
  4. Connect a voltmeter from terminal S of the engine harness to ground.
  5. Select DC volts.
  6. Turn the ignition ON, but keep the engine OFF.

Does the voltmeter display DC volts greater than the specified value?

300 mV DC

Go to Step 6

Go to Step 5

5

Inspect circuit 1230 of the Engine Wiring Harness for an open or short to ground. Refer to Electrical Diagnosis, Section 8.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

6

Connect a test lamp from terminal E to terminal V of the engine harness.

Does the test lamp light?

--

Go to Step 8

Go to Step 7

7

Inspect circuit 1231 of the Engine Wiring Harness for an open. Refer to Electrical Diagnosis, Section 8.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 16

8

  1. Turn the ignition OFF.
  2. Install test harness J 35616-A to the Automatic Transmission Wiring Harness 20-way connector.
  3. Connect an ohmmeter from terminal S to terminal V.

Does the ohmmeter display a resistance value within the specified range?

1300-1950ohms

Go to Step 13

Go to Step 9

9

Is the resistance greater than the specified value?

1950ohms

Go to Step 10

Go to Step 11

10

Inspect circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for an open. Refer to Electrical Diagnosis, Section 8.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

11

Is the resistance less than the specified value?

1300ohms

Go to Step 12

--

12

Inspect circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for a short together. Refer to Electrical Diagnosis, Section 8.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

13

Connect an ohmmeter from terminal A to the transmission case.

Is the resistance less than the specified value?

100ohms

Go to Step 14

--

14

Inspect circuit 1230 and circuit 1231 of the Automatic Transmission Wiring Harness for a short to ground. Refer to Electrical Diagnosis, Section 8.

Did you find and correct the condition?

--

Go to Step 17

Go to Step 15

15

Replace the Automatic Transmission Input (Shaft) Speed sensor. Refer to Automatic Transmission Input (Shaft) Speed Sensor Replacement in On-Vehicle Service.

Is the replacement complete?

--

Go to Step 17

--

16

Replace the PCM. Refer to PCM Replacement/Programming Section 6.

Is the replacement complete?

--

Go to Step 17

--

17

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Operate the vehicle under the following conditions:
  4. 3.1. Start the engine.
    3.2. Allow the engine to run, ensuring that the Input (Shaft) speed is greater than 50 RPM.
  5. Select Specific DTC. Enter DTC P0717.

Has the test run and passed?

--

System OK

Begin the diagnosis again. Go to Step 1