Circuit Description
The Automatic Transmission Input (Shaft) Speed Sensor (A/T ISS) provides transmission input speed to the Powertrain Control Module (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 Setting the DTC
| • | No VSS DTCs P0502 or P0503. |
| • | No TFP Val. Position Sw. DTC P1810. |
| • | The engine is running. |
| • | The TFP Val. Position Sw. indicates the vehicle is not in Park or Neutral. |
| • | The vehicle speed is greater than 8 km/h (5 mph). |
| • | 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). |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM freezes shift adapts from being updated. |
| • | DTC P0717 is stored in the PCM history. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns OFF the MIL after three consecutive trips without a failure reported. |
| • | A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported. |
| • | The PCM cancels the DTC default actions when the fault no longer exists and the ignition 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 for poor electrical connections at the PCM, the transmission 20-way connector and the A/T ISS 2-way connector for the following conditions: |
| - | A bent terminal |
| - | A backed out terminal |
| - | A damaged terminal |
| - | Poor 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 for reference. Using the Clear Info function will erase the stored 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 from the transmission 20-way connector to the A/T ISS for an open or short to ground. Refer to General Electrical Diagnosis . Did you find the condition? | -- | ||||||||
5 | Inspect circuit 1231 from the transmission 20-way connector to the A/T ISS for an open or short to ground. Refer to General Electrical Diagnosis . Did you find the condition? | -- | ||||||||
6 | Replace the automatic transmission wiring harness. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||||
7 | Replace the A/T ISS. Refer to Unit Repair. Is the replacement complete? | -- | -- | |||||||
Is the AC voltage greater than the specified value? | 0.150 mV (50 Hz) | |||||||||
9 | Inspect circuit 1230 from the engine 20-way connector to the PCM connector for an open or short to ground. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | ||||||||
10 | Inspect circuit 1231 from the engine 20-way connector to the PCM connector for an open or short to ground. Refer to General Electrical Diagnosis . Did you find and correct the condition? | -- | -- | |||||||
11 | Replace the PCM. Refer to PCM Replacement/Programming . Is the replacement complete? | -- | -- | |||||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
