Circuit Description
The automatic transmission input (shaft) speed sensor (A/T ISS) provides transmission input speed to the PCM. The A/T ISS is a permanent magnet (PM) generator. The sensor mounts into the transmission case and maintains a slight air gap between the sensor and the drive sprocket. The PM generator produces an AC voltage as the drive sprocket 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 a low input speed and the vehicle has a large vehicle speed, then DTC P0717 sets. DTC P0717 is a type B DTC.
Conditions for Running the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | No TFP manual valve position switch DTC P1810. |
| • | The engine is running. |
| • | The TFP manual valve position switch indicates the vehicle is not in PARK or NEUTRAL. |
| • | The vehicle speed is greater than 8 km/h (5 mph). |
Conditions for Setting the DTC
The input speed is less than 100 RPM for 5 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 commands maximum line pressure. |
| • | The PCM freezes shift adapts from being updated. |
| • | The PCM stores DTC P0717 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
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 PCM history. |
| • | 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 fault no longer exists and the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | If the engine is running and the vehicle is moving above 12 km/h (7 mph), then the input speed must be non-zero. |
| • | Inspect the wiring at the PCM, the transmission 20-way connector and the A/T ISS 2-way connector 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 condition, 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.
-
This step tests the A/T ISS for correct resistance.
-
This step verifies the wiring from the transmission 20-way connector to the PCM, and tests the ability of the A/T ISS to produce an AC current.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||||||||
2 |
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 transmission input speed greater than the specified value? | 500 RPM | Go to Diagnostic Aids | |||||||
Is the resistance within the specified range? | 615-835 ohms | |||||||||
4 | Inspect circuit 1230 of the transmission wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
5 | Inspect circuit 1231 of the transmission wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
6 | Replace the automatic transmission wiring harness. Refer to Wire Harness Disconnect and Wiring Harness Removal in the 4T40-E/4T45-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
7 | Replace the A/T ISS. Refer to Input Speed Sensor Removal in the 4T40-E/4T45-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||||
Is the AC voltage greater than the specified value? | 0.150 mV (50 Hz) | |||||||||
9 | Inspect circuit 1230 of the engine wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | ||||||||
10 | Inspect circuit 1231 of the engine wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Was the condition found? | -- | -- | |||||||
11 | Repair the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | -- | |||||||
12 | Replace the PCM. Refer to PCM Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||||
13 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
