The automatic transmission input shaft speed sensor (AT ISS) is a permanent magnet generator. The AT ISS mounts in the transmission case facing the drive sprocket of the input shaft. As the drive sprocket rotates, an AC voltage is induced and transmitted to the powertrain control module (PCM). The PCM converts the AC voltage into a digital signal. The PCM uses the input shaft speed signal to determine shift timing, torque converter clutch slip speed and gear ratio.
If the PCM detects an unrealistic change in RPM from the AT ISS, then DTC P0716 sets. DTC P0716 is a type B DTC.
• | No TP DTCs P0121, P0122 or P0123. |
• | No VSS DTCs P0502 or P0503. |
• | No AT ISS DTC P0717. |
• | No shift solenoid valve performance DTCs P0751, P0752, P0756, or P0757. |
• | No shift solenoid valve electrical DTCs P0973, P0974, P0976, or P0977. |
• | The engine run time is greater than 5 seconds. |
• | The TP angle is 12 percent or greater. |
• | The vehicle speed is 16 km/h (10 mph) or greater. |
• | The transmission input shaft speed is greater than 1,050 RPM for at least 2 seconds. |
• | The transmission input shaft speed has not increased by 500 RPM or greater for at least 2 seconds. |
The transmission input shaft speed drops by 1,000 RPM or greater for at least 1 second.
• | 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 commands maximum line pressure. |
• | The PCM inhibits TCC engagement. |
• | The PCM calculates input shaft speed from vehicle speed and commanded gear. |
• | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
• | The PCM stores DTC P0716 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | 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. |
• | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
• | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests the AT ISS for correct resistance.
This step tests the AT ISS high signal circuit for being shorted to another circuit within the transmission.
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 - 4.6L | ||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM. Is the transmission input speed greater than the specified value? | 500 RPM | Go to Intermittent Conditions in Engine Controls - 4.6L | Go to Step 3 | ||||
Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure within the specified range? | 1260-1,872 ohms | Go to Step 7 | Go to Step 4 | |||||
4 | Does the resistance measure greater than the specified value? | 1,872 ohms | Go to Step 5 | Go to Step 6 | ||||
5 |
Refer to Circuit Testing in Wiring Systems. Did you find a high resistance or open condition? | -- | Go to Step 11 | Go to Step 12 | ||||
6 | Test the high signal circuit and the low signal circuit of the AT ISS for being shorted together between the AT inline 20-way connector and the AT ISS. Refer to Circuit Testing in Wiring Systems. Did you find the condition? | -- | Go to Step 11 | Go to Step 12 | ||||
7 | Measure the resistance between terminal S of the J 44152 and ground. Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure less than the specified value? | 10M ohms | Go to Step 11 | Go to Step 8 | ||||
Measure the resistance between terminal S and all other terminals, except terminal V, of the J 44152 . Refer to Automatic Transmission Inline 20-Way Connector End View . Does the resistance measure between terminal S and any other terminal, except terminal V, less than the specified value? | 10M ohms | Go to Step 11 | Go to Step 9 | |||||
9 | Test the high signal circuit of the AT ISS for a high resistance, an open, a short to ground or a short to voltage between the PCM connector C3 and the AT inline 20-way connector. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 10 | ||||
10 | Test the low signal circuit of the AT ISS for a high resistance or an open between the PCM connector C3 and the AT inline 20-way connector. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 14 | Go to Step 13 | ||||
11 |
Important: The automatic transmission wiring harness consists of 2 separate harnesses, the Automatic Transmission Wiring Harness Assembly, GM P/N 15320475, and the Automatic Transmission Wiring Extension Harness Assembly, GM P/N 15320478. In order to avoid the unnecessary replacement of parts, only replace the Automatic Transmission Wiring Harness Assembly, GM P/N 15320475. Replace the automatic transmission wiring harness. Refer to Input Speed Sensor and Wiring Harness Removal in the 4T80-E section of the Transmission Unit Repair Manual. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
12 | Replace the AT ISS. Refer to Input Speed Sensor and Wiring Harness Removal in the 4T80-E section of the Transmission Unit Repair Manual. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
13 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.6L. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||
14 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 15 | Go to Step 2 | ||||
15 | 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 - 4.6L | System OK |