What this code means
P0717 means the control module may not be receiving a usable input shaft, or mainshaft, speed sensor signal from the automatic transmission.
What the vehicle may do
- The vehicle may shift abnormally.
- The transmission may go into a limited operating strategy.
- Warning lights may be present.
Possible fault areas
- Possible fault areas can include the input shaft speed sensor circuit, sensor connector, signal wiring, power or ground side of the circuit, and the control module side of the same
- This code is often approached as an electrical signal problem rather than an internal transmission mechanical problem.
Diagnostic path
Open and diagnostic frame
On this 2010 to 2015 Honda Civic with the 1.8 gas engine, P0717 means the PCM may not be seeing a usable input shaft, or mainshaft, speed signal from the automatic transmission. The driver may notice abnormal shifting, limited transmission operation, or warning lights, but the key point for this diagnostic path is that this code is handled as an electrical circuit problem. It is not diagnosed as a mechanical fault inside the transmission. Before getting into the checks, save the freeze data and any on-board snapshot with the HDS, then start with the basic system checks so you know the fault conditions you are trying to duplicate.
Verify the problem first
First, verify the complaint before taking the circuit apart. Turn the ignition switch to ON (II), clear the DTC with the HDS, then safely set the car up so the front wheels can rotate freely. Block the rear wheels and raise the front, or use a lift, but make sure the vehicle is securely supported. Start the engine, turn VSA off with the VSA OFF button, put the shift lever in D, and run the vehicle at speeds over 12 mph (20 km/h). In the HDS A/T Data List, compare input shaft, or mainshaft, speed against output shaft, or countershaft, speed. Then slow down and stop the wheels. If the two speeds are about the same, treat it as an intermittent failure and the system is OK at this time. If they are not about the same, the failure is duplicated and you move into the circuit checks.
Check the VCC2 feed
Next, check the VCC2 line for an open. Turn the ignition switch to LOCK (0), disconnect the input shaft speed sensor 3P connector, then turn the ignition switch back to ON (II). Measure voltage from terminal No. 3, the YEL/BLU wire, to body ground. You are looking for about 5 V. If about 5 V is present, the VCC2 wire is OK and you continue to the next signal check. If it is not present, repair the open in the VCC2 wire between the input shaft speed sensor and the PCM, then go to the final verification.
Use the NM voltage check to choose the next branch
With the ignition still ON (II) and the input shaft speed sensor 3P connector still disconnected, measure the NM circuit. Check voltage from terminal No. 2, the WHT/RED wire, to body ground. Again, the question is whether there is about 5 V. If there is about 5 V, continue by checking the SG2 ground side. If there is not about 5 V, move to the NM circuit short and open check.
If NM voltage is present, check SG2 continuity
If the NM check showed about 5 V, turn the ignition switch to LOCK (0) and check the SG2 line. With the input shaft speed sensor 3P connector disconnected, check continuity from terminal No. 1, the GRN/YEL wire, to body ground. If there is continuity, the SG2 wire is OK, so replace the input shaft, or mainshaft, speed sensor, then go to the final verification. If there is no continuity, repair the open in the SG2 wire between the input shaft speed sensor and the PCM, then go to the final verification.
If NM voltage is missing, check the NM wire
If the NM voltage check did not show about 5 V, turn the ignition switch to LOCK (0), jump the SCS line with the HDS, and disconnect PCM connector B, the 49P connector. With the input shaft speed sensor 3P connector still disconnected, check continuity from terminal No. 2, the WHT/RED wire, to body ground. If there is continuity, repair a short to ground in the NM wire between the input shaft speed sensor and the PCM. If there is no continuity, the NM wire is not shorted, so repair an open in the NM wire between the input shaft speed sensor and the PCM. Either way, after the wiring repair, go to the final verification.
Verify the repair
For verification, reconnect all connectors, turn the ignition switch to ON (II), and clear the DTC with the HDS. Start the engine, turn VSA off with the VSA OFF button, put the shift lever in D, and run the vehicle at speeds over 12 mph (20 km/h). Compare input shaft speed and output shaft speed again in the HDS A/T Data List, then slow down and stop the wheels. If the speeds are about the same, troubleshooting is complete. If they are not about the same after completing the diagnostic path, replace the PCM.
Takeaway and close
The takeaway on P0717 is to prove the speed mismatch first, then stay disciplined with the electrical checks: VCC2 feed, NM signal branch, SG2 ground path, and final verification. Do not chase internal transmission mechanics for this code path. For more diagnostic training, visit stepdiagnostics.com.
Final check
A clean diagnosis usually comes from confirming the speed signal problem first, then checking the sensor circuit in order before making a repair decision.
For more guided automotive diagnostics, visit STEP Diagnostics.
