C1429: Input-shaft-speed input circuit failure

Definition

The OBD2 code C1429 indicates a failure in the input shaft speed sensor circuit, which may affect the transmission's ability to accurately determine the input shaft speed

Common causes

Faulty input shaft speed sensor
Damaged wiring or connectors
Poor electrical connections
Short circuit in the input circuit
Open circuit in the input circuit
Faulty transmission control module (TCM)
Mechanical issues in the transmission
Corrosion or dirt on sensor terminals

Common misdiagnoses

Faulty transmission control module (TCM)
Defective speed sensors
Wiring issues or shorts in the input circuit
Faulty engine control module (ECM)
Incorrectly diagnosed transmission problems
Issues with the vehicle's powertrain control module (PCM)
Problems with the vehicle's ABS system
Misinterpretation of related codes or symptoms

Troubleshooting steps

1. Check for Additional Codes

Before proceeding, use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues
2. Inspect Wiring and Connectors
3. Visually inspect the wiring and connectors associated with the input shaft speed sensor. Look for signs of damage, corrosion, or loose connections
4. Ensure that the connectors are securely attached and that there are no bent pins
5. Test the Input Shaft Speed Sensor
6. Use a multimeter to test the resistance of the input shaft speed sensor. Compare the readings to the specifications provided in the vehicle's service manual
7. If the sensor is faulty, it may need to be replaced
8. Check for Short Circuits or Open Circuits
9. Use a multimeter to check for continuity in the wiring between the sensor and the engine control module (ECM) or transmission control module (TCM)
10. Look for any short circuits to ground or open circuits that could be causing the failure
11. Inspect the Transmission Fluid
12. Check the transmission fluid level and condition. Low or contaminated fluid can affect sensor performance
13. If the fluid is dirty or burnt, consider changing it and inspecting for any debris that could indicate internal transmission issues
14. Test the ECM/TCM
15. If the sensor and wiring are in good condition, the issue may lie with the ECM or TCM. Check for software updates or reprogramming needs
16. In some cases, the control module may need to be replaced if it is determined to be faulty
17. Perform a Visual Inspection of the Transmission
18. Inspect the transmission for any signs of physical damage or leaks that could affect sensor operation
19. Clear the Codes and Test Drive
20. After performing repairs or replacements, clear the trouble codes using the OBD-II scanner
21. Take the vehicle for a test drive to see if the code reappears. Monitor the transmission performance during the drive
22. Consult a Professional
23. If the issue persists after following these steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the C1429 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect Wiring and Connectors

3. Visually inspect the wiring and connectors associated with the input shaft speed sensor. Look for signs of damage, corrosion, or loose connections

4. Ensure that the connectors are securely attached and that there are no bent pins

5. Test the Input Shaft Speed Sensor

6. Use a multimeter to test the resistance of the input shaft speed sensor. Compare the readings to the specifications provided in the vehicle's service manual

7. If the sensor is faulty, it may need to be replaced

8. Check for Short Circuits or Open Circuits

9. Use a multimeter to check for continuity in the wiring between the sensor and the engine control module (ECM) or transmission control module (TCM)

10. Look for any short circuits to ground or open circuits that could be causing the failure

11. Inspect the Transmission Fluid

12. Check the transmission fluid level and condition. Low or contaminated fluid can affect sensor performance

13. If the fluid is dirty or burnt, consider changing it and inspecting for any debris that could indicate internal transmission issues

14. Test the ECM/TCM

15. If the sensor and wiring are in good condition, the issue may lie with the ECM or TCM. Check for software updates or reprogramming needs

16. In some cases, the control module may need to be replaced if it is determined to be faulty

17. Perform a Visual Inspection of the Transmission

18. Inspect the transmission for any signs of physical damage or leaks that could affect sensor operation

19. Clear the Codes and Test Drive

20. After performing repairs or replacements, clear the trouble codes using the OBD-II scanner

21. Take the vehicle for a test drive to see if the code reappears. Monitor the transmission performance during the drive

22. Consult a Professional

23. If the issue persists after following these steps, it may be necessary to consult a professional mechanic or technician who has experience with transmission diagnostics. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the C1429 code