P1722: Gear 2 Incorrect Ratio

Definition

The OBD2 code P1722 indicates that the transmission control module has detected an incorrect gear ratio in the second gear, suggesting a potential issue with the transmission or its components

Common causes

Faulty transmission control module (TCM)
Malfunctioning transmission fluid temperature sensor
Incorrect transmission fluid level or type
Worn or damaged transmission components
Faulty gear shift linkage or cable
Defective speed sensors
Electrical issues or wiring problems
Software issues in the TCM

Common misdiagnoses

Transmission fluid issues
Faulty speed sensors
Transmission control module (TCM) problems
Incorrectly calibrated transmission
Worn or damaged transmission components
Engine control module (ECM) issues
Wiring or connector problems
Shift solenoid malfunctions

Troubleshooting steps

1. Check for Additional Codes

Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide more context and help identify related issues
2. Inspect Transmission Fluid
3. Check the transmission fluid level and condition. Low or dirty fluid can cause shifting issues
4. If the fluid is burnt or contaminated, consider changing it and the filter
5. Examine Wiring and Connectors
6. Inspect the wiring and connectors related to the transmission control module (TCM) and the transmission itself for any signs of damage, corrosion, or loose connections
7. Pay special attention to the wiring harness for the speed sensors and solenoids
8. Test Transmission Sensors
9. Check the operation of the transmission input and output speed sensors. These sensors provide critical data to the TCM for proper shifting
10. Use a multimeter to test the sensors for proper voltage and resistance
11. Inspect the Transmission Control Module (TCM)
12. Ensure that the TCM is functioning correctly. A malfunctioning TCM can lead to incorrect gear ratios
13. If necessary, reprogram or replace the TCM
14. Check for Mechanical Issues
15. Inspect the transmission for any mechanical problems, such as worn clutches, bands, or gears
16. A transmission rebuild or replacement may be necessary if significant wear or damage is found
17. Perform a Road Test
18. After addressing any issues found, perform a road test to see if the code returns. Pay attention to how the transmission shifts through the gears
19. Clear the Code
20. After repairs, clear the trouble codes using the OBD-II scanner and see if the P1722 code reappears after driving the vehicle
21. Consult a Professional
22. If the issue persists after performing these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis. By following these steps, you can systematically identify and address the underlying issues causing the P1722 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect Transmission Fluid

3. Check the transmission fluid level and condition. Low or dirty fluid can cause shifting issues

4. If the fluid is burnt or contaminated, consider changing it and the filter

5. Examine Wiring and Connectors

6. Inspect the wiring and connectors related to the transmission control module (TCM) and the transmission itself for any signs of damage, corrosion, or loose connections

7. Pay special attention to the wiring harness for the speed sensors and solenoids

8. Test Transmission Sensors

9. Check the operation of the transmission input and output speed sensors. These sensors provide critical data to the TCM for proper shifting

10. Use a multimeter to test the sensors for proper voltage and resistance

11. Inspect the Transmission Control Module (TCM)

12. Ensure that the TCM is functioning correctly. A malfunctioning TCM can lead to incorrect gear ratios

13. If necessary, reprogram or replace the TCM

14. Check for Mechanical Issues

15. Inspect the transmission for any mechanical problems, such as worn clutches, bands, or gears

16. A transmission rebuild or replacement may be necessary if significant wear or damage is found

17. Perform a Road Test

18. After addressing any issues found, perform a road test to see if the code returns. Pay attention to how the transmission shifts through the gears

19. Clear the Code

20. After repairs, clear the trouble codes using the OBD-II scanner and see if the P1722 code reappears after driving the vehicle

21. Consult a Professional

22. If the issue persists after performing these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis. By following these steps, you can systematically identify and address the underlying issues causing the P1722 code