Circuit Description
The automatic transmission input (shaft) speed (A/T ISS) sensor provides transmission input speed to the powertrain control module (PCM). The A/T 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 D DTC. For California emissions vehicles, DTC P0716 is a type B DTC.
Conditions for Running the DTC
| • | No throttle position (TP) sensor DTCs P0121, P0122 or P0123. |
| • | No OSS DTC P0502 or P0503. |
| • | No A/T ISS DTC P0717. |
| • | No shift solenoid DTC 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 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
| • | For California emission vehicles only, the PCM illuminates the malfunction indicator lamp (MIL). |
| • | The PCM commands maximum line pressure. |
| • | The PCM freezes shift adapts. |
| • | The PCM stores DTC P0716 in PCM history. |
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
| • | Inspect the wiring at the PCM, the OSS connector and all other circuit connecting points for the following: |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Reduced terminal tension |
| - | A chafed wire |
| - | A broken wire inside the insulation |
| - | Moisture intrusion |
| - | Corrosion |
| - | The A/T ISS sensor harness being near the DIS components or the ignition wires. |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | First diagnose and clear any engine DTCs or TP sensor codes that are present. Then inspect for any transmission DTCs that may have reset. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests for proper operation to the A/T ISS sensor.
-
This step tests for proper A/T ISS circuit operation up to the PCM connections. Remove the fuel pump relay in order to eliminate a flooding condition during this step.
Step | Action | Value(s) | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||
Important: Before clearing the DTCs, 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 Scan Tool Transmission ISS more than 800 RPM? | -- | Go to Diagnostic Aids | ||||||
3 |
Is the sensor resistance within the specified range? | 1042-2088Ω | ||||||
4 | Inspect CKT 1230 (RED/BLK) for an open or a short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was an open or short to ground condition found? | -- | ||||||
5 | Inspect CKT 1231 (BLU/WHT) for an open. Refer to General Electrical Diagnosis in Wiring Systems. Was an open condition found? | -- | ||||||
Refer to Automatic Transmission Components. Is the voltage above the specified value? | 0.5 volts AC | Go to Diagnostic Aids | ||||||
7 | Repair the open or short to ground in CKT 1230 (RED/BLK). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||
8 | Repair the open in CKT 1231 (BLU/WHT). Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||
9 | Replace the ISS sensor. Refer to Vehicle Speed Sensor Replacement. Is the replacement complete? | -- | -- | |||||
10 |
Was the condition found? | -- | ||||||
11 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
12 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
