GM Service Manual Online
For 1990-2009 cars only

Object Number: 362643  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 (A/T ISS) sensor is a permanent magnet with a coil of wire wound around it. The A/T ISS sensor mounts in the case cover facing the drive sprocket of the input shaft. As the drive sprocket is driven by the turbine shaft, an AC signal is induced in the input speed sensor. Higher vehicle speeds induce a higher frequency and voltage at the sensor.

An air gap of 0.08-2.12 mm (0.032-0.0834 in) must be maintained between the sensor and the drive sprocket to insure proper operation of the A/T ISS sensor. The A/T ISS sensor input is used by the PCM 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.

This diagnostic indicates stuck, erratic, or intermittent values, indicating poor performance of the system.

If the PCM detects an unrealistically large change in data from the A/T ISS sensor in a short period of time, then DTC P0716 sets. DTC P0716 is a Type B DTC.

Conditions for Running the DTC

    • No TP sensor DTCs P0121, P0122 or P0123 are set.
    • No VSS DTCs P0502 or P0503 are set.
    • No A/T ISS sensor DTC P0717 is set and DTC P0717 has passed this ignition cycle.
    • No 1-2, 3-4 shift solenoid valve DTCs P0751 or  P0753 are set.
    • No 2-3 shift solenoid valve DTCs P0756 or P0758 are set.
    • The engine speed is greater than 500 RPM for 5 seconds and not in fuel shut off.
    • The TP angle is greater than 14%.
    • The vehicle speed is greater than 8 km/h (5 mph).

Conditions for Setting the DTC

The input shaft speed changes by greater than 1300 RPM in 0.8 seconds.

Action Taken When the DTC Sets

    • The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the conditions for setting the DTC are met.
    • The PCM freezes shift adapts.
    • The PCM inhibits TCC.
    • The PCM inhibits 4th gear if the transmission is in Hot Mode.
    • The PCM stores DTC P0716 in PCM history.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
    • A scan tool clears the DTC from the PCM history.
    • The PCM clears the DTC from the PCM history if the vehicle completes 40 consecutive warm-up cycles without an 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

    • Check for electromagnetic interference (EMI) in circuits 1230 (RED/BLK) and 1231 (DK BLU/WHT). EMI may be induced by a misrouted wiring harness along the spark plug wires.
    • Inspect the wiring at the PCM, the transmission 20-way connector, the A/T ISS sensor connector and all other circuit connecting points for the following conditions:
       - A backed out terminal
       - A damaged terminal
       - Reduced terminal tension
       - A chafed wire
       - A broken wire inside the insulation
       - Moisture intrusion
       - Corrosion
    • When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

Test Description

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

  1. This step verifies that the PCM receives a signal from the A/T ISS sensor.

  2. This step checks the integrity of the A/T ISS sensor and the automatic transmission wiring harness assembly.

  3. This step checks the integrity of the circuitry from the transmission 20-way connector to the PCM.

  4. Because of the harsh conditions inside the transmission, repairing the automatic transmission (A/T) wiring harness assembly is not acceptable. It must be replaced if it is damaged in any way.

DTC P0716 Input Speed Sensor Circuit Intermittent

Step

Action

Value(s)

Yes

No

1

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

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls

2

  1. Install the Scan Tool .
  2. Start the engine.
  3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. Using the Clear Info function will erase the stored Freeze Frame and Failure Records from the PCM.

  4. Record the Freeze Frame and Failure Records.
  5. Clear the DTCs.
  6. Monitor transmission ISS on the scan tool.

Does the scan tool display a transmission input shaft speed greater than the specified value?

100 RPM

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the transmission 20-way connector.
  3. Connect the J 39775 jumper harness to the transmission side of the 20-way connector.
  4. Connect the J 39200 digital multimeter (DMM) from terminal S to terminal V of the J 39775 jumper harness.
  5. Refer to Automatic Transmission Inline Harness Connector End View .

  6. Select AC volts on the J 39200 DMM.
  7. Important: Additional DTCs will set.

  8. Start the engine.

Does the J 39200 DMM display an AC voltage greater than the specified value?

0.5 volts

Go to Step 4

Go to Step 6

4

  1. Inspect circuit 1230 (RED/BLK) of the engine wiring harness for an open, short to circuit 1231 (DK BLU/WHT) or short to ground.
  2. Inspect circuit 1231 (DK BLU/WHT) of the engine wiring harness for an open, short to circuit 1230 (RED/BLK) or short to ground.
  3. Refer to General Electrical Diagnosis in Wiring Systems.

Was a condition found?

--

Go to Step 8

Go to Step 5

5

Inspect PCM connector C1 for bent, damaged or backed out connector pins.

Was a condition found?

--

Go to Step 7

Go to Step 11

6

  1. Inspect circuit 1230 (BLK) of the automatic transmission wiring harness assembly for an open, a short to circuit 1231 (DK GRN) or a short to ground.
  2. Inspect circuit 1231 (DK GRN) of the automatic transmission wiring harness assembly for an open, a short to circuit 1230 (BLK) or a short to ground.

Refer to General Electrical Diagnosis in Wiring Systems.

Was a condition found?

--

Go to Step 9

Go to Step 10

7

Repair the connector as necessary.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 12

--

8

Repair the circuit(s) as necessary.

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 12

--

9

Replace the automatic transmission wiring harness assembly.

Refer to Solenoids and Wiring Harness Replacement .

Is the replacement complete?

--

Go to Step 12

--

10

Replace the automatic transmission input shaft speed sensor.

Refer to Input Speed Sensor Replacement .

Is the replacement complete?

--

Go to Step 12

--

11

Replace the PCM.

Refer to Powertrain Control Module Replacement/Programming in Engine Controls.

Is the replacement complete?

--

Go to Step 12

--

12

Perform the following procedure in order to verify the repair:

  1. Select DTC.
  2. Select Clear Info.
  3. Start the engine.
  4. Select Specific DTC.
  5. Enter DTC P0716.

Has the test run and passed?

--

System OK

Go to Step 1