GM Service Manual Online
For 1990-2009 cars only

Object Number: 508741  Size: MF
Automatic Transmission Components
Automatic Transmission Controls Schematics
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The automatic transmission input (shaft) speed (AT ISS) sensor provides transmission input speed to the powertrain control module (PCM). The AT ISS sensor is a permanent magnet (PM) generator. The sensor mounts into the transmission case and maintains a slight air gap between the sensor and the forward clutch housing. The PM generator produces an AC voltage as the forward clutch housing rotor teeth pass through the sensor's magnetic field. The AC voltage level increases as the turbine shaft speed increases. The PCM converts the AC voltage into a digital signal. The PCM determines actual turbine speed using the digital signal. The PCM uses the input speed to calculate torque converter slip speed, and gear ratios.

When the PCM detects an unreasonably large change in the input speed, in a very short period of time, then DTC P0716 sets. DTC P0716 is a type C DTC. For California emissions vehicles, DTC P0716 is a type B DTC.

Conditions for Running the DTC

    • No TP sensor DTCs P0121, P0122 or P0123.
    • No OSS DTC P0502 or P0503.
    • No ISS DTC P0717.
    • No 1-2 shift solenoid DTCs P0751 or P0753.
    • The system voltage is 8.0-18.0 volts.
    • The TP angle is greater than 10%.
    • The vehicle speed is greater than 44 km/h (27 mph).
    • The engine is running greater than 300 RPM for more than 7 seconds.

Conditions for Setting the DTC

    • The transmission is not in PARK or NEUTRAL.
    • The input speed varies by 1300 RPM for greater than 5 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip for all California emission equipped vehicles in which the Conditions for Setting the DTC are met.
    • The PCM commands maximum line pressure.
    • The PCM freezes shift adapts.
    • The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame (Calif. only) and Failure Records (Calif. and Federal).
    • The PCM stores the DTC P0716 in PCM history during the second consecutive trip (Calif.) or the first trip (Federal) in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC

    • For California emissions, the PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool can clear the MIL/DTC.
    • For California emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without an emission related diagnostic fault occurring.
    • For Federal emissions, the PCM clears the DTC from PCM history if the vehicle completes 40 consecutive warm-up cycles without a non-emission related diagnostic fault occurring.
    • The PCM cancels the DTC default actions when the fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM.

Diagnostic Aids

    • First diagnose and clear any engine DTCs or TP sensor codes that are present. Then inspect for any transmission DTCs that may have reset.
    • Inspect the connectors at the PCM, the ISS sensor 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. This step tests for proper operation to the ISS sensor.

  2. This step tests for proper ISS circuit operation up to the PCM connections. Remove the fuel pump relay in order to eliminate a flooding condition during this step.

DTC P0716

Step

Action

Value(s)

Yes

No

1

Did you perform the Powertrain Diagnostic System Check?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

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 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. Clear the DTC.
  6. Raise and support the rear axle assembly.
  7. Start the engine.
  8. Place the transmission in any drive range.

With the drive wheels rotating, does the Scan Tool Transmission ISS increase with the drive wheel speed?

--

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the PCM connector C2.
  3. Using the J 39200 digital multimeter (DMM) and the J 35616-A connector test adapter kit, measure the resistance between harness connector terminals C2-22 and C2-23.

Does the resistance measure within the specified range?

1377-3355 ohms

Go to Step 4

Go to Step 7

4

Measure the resistance from terminal C2-22 to ground.

Does the resistance measure greater than the specified value?

50 K ohms

Go to Step 5

Go to Step 8

5

  1. Reconnect the PCM connector C2.
  2. Disconnect the engine wiring harness form the ISS assembly.
  3. Turn ON the ignition, with the engine OFF.
  4. Test the high circuit (CKT 1230) of the ISS assembly for a short to power.
  5. Test the low circuit (CKT 1231) of the ISS assembly for a short to power.
  6. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 12

6

  1. Disconnect the engine wiring harness from the ISS assembly.
  2. Measure the resistance of the ISS assembly.

Does the resistance measure within the specified range?

1377-3355 ohms

Go to Step 7

Go to Step 11

7

Was the resistance measured in Step 3 greater than the specified value?

3355 ohms

Go to Step 9

Go to Step 10

8

  1. Test the high circuit (CKT 1230) of the ISS assembly for a short to ground.
  2. Test the low circuit (CKT 1231) of the ISS assembly for a short to ground.
  3. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

--

9

  1. Test the high circuit (CKT 1230) of the ISS assembly for an open.
  2. Test the low circuit (CKT 1231) of the ISS assembly for an open.
  3. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

--

10

Test the high circuit (CKT 1230) and the low circuit (CKT 1231) of the ISS assembly for a short together.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 13

--

11

Replace the ISS assembly.

Refer to Vehicle Speed Sensor Replacement.

Did you complete the replacement?

--

Go to Step 13

--

12

Replace the PCM.

Refer to Powertrain Control Module Replacement in Engine Controls.

Did you complete the replacement?

--

Go to Step 13

--

13

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. • The transmission output speed is greater than 450 RPM.
    • No RPM change greater than 450 RPM.
    • All conditions are met for 2 seconds.
  5. Select Specific DTC.
  6. Enter DTC P0716.

Has the test run and passed?

--

System OK

Go to Step 1