Diagnostic Instructions
DTC Descriptors
DTC P0716: Input Speed Sensor (ISS) Performance
DTC P0717: Input Speed Sensor (ISS) Circuit Low Voltage
Diagnostic Fault Information
| • | DTC P0716 detects a large change in the input speed signal in a very short period of time; an unrealistic change indicates an intermittent fault. |
| • | DTC P0717 detects a very low input speed when the vehicle speed is greater than a calibrated value indicates a continuous fault. |
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
| Signal Performance
|
ISS High Signal
| P0716, P0717
| P0716, P0717
| P0716, P0717
| P0716, P0717
|
ISS Low Signal
| --
| P0716, P0717
| --
| P0716, P0717
|
Typical Scan Tool Data
Transmission Input Speed Sensor
Circuit
| Short to Ground
| Open/High Resistance
| Short to Voltage
|
Operating Conditions:
Engine running in PARK, normal operating temperature
Parameter Normal Range:
500-800 RPM
|
Transmission ISS
| 0 RPM
| 0 RPM
| 0 RPM
|
Circuit/System Description
The automatic transmission ISS is a permanent magnet with a coil of wire wound around it. The ISS mounts in the case cover facing the reluctor wheel of the input shaft. As the reluctor wheel is driven by the turbine shaft, an AC signal is induced in the
input speed sensor. Higher vehicle speeds induce a higher frequency and a higher voltage at the sensor. There is a fixed air gap between the sensor and the teeth on the sensor reluctor wheel. The ISS input is used by the transmission control module (TCM)
in order to control line pressure, torque converter clutch (TCC) apply and release, and transmission shift patterns. This sensor is also used to calculate the appropriate gear ratios and TCC slippage.
Conditions for Running the DTC
P0716
| • | No ISS DTC P0716 or P0717. |
| • | No OSS/VSS DTC P0722 or P0723. |
| • | No TP sensor DTC P0120 or P0220. |
| • | No 1-2 shift solenoid valve DTC P0752, P0973, or P0974. |
| • | Ignition voltage is between 8.0 and 18.0 volts. |
| • | The engine speed is greater than 500 RPM for 5 seconds and not in fuel cut-off. |
| • | The vehicle speed is 16 km/h (10 mph) or greater. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
| • | The ISS is greater than 1,050 RPM for at least 2 seconds. |
| • | An increase in ISS is 500 RPM or less for at least 2 seconds. |
| • | The calc. throttle position is 8 percent or greater. |
P0717
| • | No OSS/OSS DTC P0722 or P0723. |
| • | Ignition voltage is between 8.0 and 18.0 volts. |
| • | The engine speed is greater than 500 RPM for 5 seconds. |
| • | The vehicle speed is 16 km/h (10 mph) or greater. |
| • | The engine torque is greater than 50 N·m (37 lb ft). |
Conditions for Setting the DTC
P0716
The input shaft speed changes by 1,000 RPM or greater for 3.25 seconds.
P0717
The input shaft speed is less than 50 RPM for 4.5 seconds.
Action Taken When the DTC Sets
| • | DTC P0716 and P0717 are type B DTCs. |
| • | The TCM commands maximum line pressure. |
| • | The TCM freezes transmission adaptive functions. |
| • | The TCM calculates input speed based on engine speed and gear ratio. |
Conditions for Clearing the DTC
DTC P0716 and P0717 are type B DTCs.
Diagnostic Aids
| • | DTC P0716 detects a large change in the input speed signal in a very short period of time; an unrealistic change indicates an intermittent fault. |
| • | DTC P0717 detects a very low input speed when the vehicle speed is greater than a calibrated value indicates a continuous fault. |
| • | Inspect the ISS, wire harness, connector, and TCM for metallic debris, damage, or misalignment. Ensure the wiring harness is not stretched too tightly or other components are pressing on the automatic transmission inline 20-way connector body. Also
inspect for proper clearance to any other components and wiring. |
Reference Information
Schematic Reference
Automatic Transmission Controls Schematics
Connector End View Reference
Description and Operation Reference
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
| • | J 44257
Main Wiring Harness Connector Remover |
Circuit/System Verification
Engine running. Observe the transmission ISS on the scan tool while varying the engine speed. The transmission ISS should vary with the engine speed and not drop out.
Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
Important: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Ignition OFF, using the remover
J 44257
, disconnect the automatic transmission inline 20-way connector and install the jumper harness
J 44152
on
the transmission pass-thru connector.
- Using the light-blue test probes J 35616-65B from the most current J 35616 GM terminal test kit, test for 820-1428 Ω between the ISS high signal circuit jumper harness pin S and the ISS low signal circuit jumper harness pin
V.
| ⇒ | If greater than the specified range, test the affected circuits for an open/high resistance. If both circuits test normal, replace the ISS. |
| ⇒ | If less than the specified range, test the affected circuits for a shorted together condition. If both circuits test normal, replace the ISS. |
- Test for greater than 10K Ω between the ISS high signal circuit jumper harness pin S and all other circuits of the jumper harness
J 44152
, except the ISS low signal circuit jumper harness
pin V.
| ⇒ | If less than the specified range, the affected circuits are shorted together. Replace the transmission internal wire harness. |
- Test for greater than 250 Ω from the ISS high signal circuit jumper harness pin S and the ISS low signal circuit jumper harness pin V to the transmission case.
| ⇒ | If less than the specified value, test the affected circuits for a short to the transmission case. If both circuits test normal, replace the ISS. |
- Using the remover
J 44257
, remove the jumper harness
J 44152
from the transmission pass-thru connector and install it on the engine side of
the AT inline 20-way connector.
- Disconnect the X1 harness connector at the TCM.
Important: When test probing TCM harness terminals, it is imperative to use the proper test probe from the most current version of the J 35616 GM terminal test kit. Use of the brown J 35616-6 (1.00 mm) PCM probe in a 0.64 mm
terminal will deform the terminal, resulting in intermittent open conditions. The correct probe for TCM harnesses is the light blue J 35616-64B probe.
- Using the light blue probes J 35616-64B, test for greater than 250 Ω from the ISS high signal circuit jumper harness terminal S and the ISS low signal circuit jumper harness terminal V to a good ground.
| ⇒ | If less than the specified value, test the affected circuit for a short to ground. |
- Using the light blue probes J 35616-64B , test for greater than 10K Ω between the ISS high signal circuit jumper harness terminal S and all other circuits of the jumper harness
J 44152
.
| ⇒ | If less than the specified value, the affected circuits are shorted together. |
- Using the light blue probes J 35616-64B , test for greater than 10K Ω between the ISS low signal circuit jumper harness terminal V and all other circuits of the jumper harness
J 44152
.
| ⇒ | If less than the specified value, the affected circuits are shorted together. |
- Using the light blue probes J 35616-64B, test the ISS high signal circuit for less than 10 Ω between the jumper harness
J 44152
terminal S and terminal 3 X1 TCM.
| ⇒ | If greater than the specified value, repair the open or high resistance in the affected circuit. |
- Using the light blue probes J 35616-64B, test the ISS low signal circuit for less than 10 Ω between the jumper harness
J 44152
terminal V and terminal 26 X1 TCM.
| ⇒ | If greater than the specified value, repair the open or high resistance in the affected circuit. |
- Using a 5A fused jumper wire and the light blue probes J 35616-64B, test for greater than 10K Ω between the ISS high signal circuit terminal 3 X1 TCM and all other circuits of X1 TCM.
| ⇒ | If less than the specified value, the affected circuits are shorted together. |
- Using a 5A fused jumper wire and the light blue probes J 35616-64B, test for greater than 10K Ω between the ISS low signal circuit terminal 26 X1 TCM and all other circuits of X1 TCM.
| ⇒ | If less than the specified value, the affected circuits are shorted together. |
- If all circuits and connections test normal, replace the TCM.
Component Testing
- Ignition OFF, using the remover
J 44257
, disconnect the automatic transmission (AT) inline 20-way connector and install the jumper harness
J 44152
on the transmission pass-thru connector.
- Using the light-blue test probe J 35616-65B from the most current J 35616 GM terminal test kit, test for 820-1428 Ω between the ISS high signal circuit jumper harness pin S and the ISS low signal circuit jumper harness pin V.
| ⇒ | If greater than the specified range, test the affected circuits for an open/high resistance. If both circuits test normal, replace the ISS. |
| ⇒ | If less than the specified range, test the affected circuits for a shorted together condition. If both circuits test normal, replace the ISS. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
