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 mounts in the transmission case facing the drive sprocket of the input shaft. An air gap of 0.045-0.109 in. between the sensor and the drive sprocket must be maintained so that an accurate AC voltage can be transmitted. Sensor voltage varies from 0.5 volts AC at 100 RPM to more than 100 volts at 8000 RPM. The A/T ISS has a resistance value of 1300-1950 ohms.
When the Powertrain Control Module (PCM) detects a low input speed while the vehicle and engine speeds are high, then DTC P0717 sets. DTC P0717 is a Type B DTC.
Conditions for Setting the DTC
| • | No TP DTCs P0121, P0122 or P0123. |
| • | No VSS DTCs P0502 or P0503. |
| • | No TFP Val. Position Sw. DTC P1810. |
| • | The engine run time is greater than 5 seconds. |
| • | The engine is not in fuel cut off. |
| • | The transmission is not in Park or Neutral. |
| • | The vehicle speed is greater than 16 km/h (10 mph). |
| • | The input (shaft) speed is less than 50 RPM for 2 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the Malfunction Indicator Lamp (MIL). |
| • | SERVICE ENGINE SOON, SERVICE TRANSMISSION displays on the Driver Information Center (DIC). |
| • | The PCM commands default line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM disables steady state adapts. |
| • | The PCM disables upshift adapts. |
| • | The PCM disables garage shift adapts. |
| • | The PCM inhibits garage shift pressure calculations. |
| • | The PCM calculates input (shaft) speed from vehicle speed and commanded gear. |
| • | 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
| • | Inspect the wiring 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 |
| • | When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change. |
| • | Inspect the transmission 20-way connector for transmission fluid. |
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? | -- | Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls | |||||
2 |
Important: Before clearing the DTC(s), 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? | 1300-1950 ohms | |||||||
4 | Inspect circuit 1230 of the automatic transmission wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||
5 | Inspect circuit 1231 of the automatic transmission wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find the condition? | -- | ||||||
6 | Replace the automatic transmission wiring harness. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||
7 | Replace the A/T ISS. Refer to Transmission Overhaul in the 4T80-E Section of the Transmission Unit Repair Manual. Is the replacement complete? | -- | -- | |||||
Is the AC voltage greater than the specified value? | 0.5 V AC | |||||||
9 | Inspect circuit 1230 of the engine wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | ||||||
10 | Inspect circuit 1231 of the engine wiring harness for an open or short to ground. Refer to General Electrical Diagnosis in Wiring Systems. Did you find and correct the condition? | -- | -- | |||||
11 | Replace the PCM. Refer to Powertrain Control Module Replacement/Programming in Engine Controls. Is the replacement complete? | -- | -- | |||||
12 | In order to verify your repair, perform the following procedure:
Has the test run and passed? | -- | System OK |
