P078E: Shift Timing Solenoid B Intermittent

Definition

The OBD2 code P078E indicates an intermittent issue with the Shift Timing Solenoid B, which affects the transmission's ability to shift gears properly

Common causes

Faulty shift timing solenoid B
Wiring issues or damaged connectors
Low transmission fluid level
Contaminated transmission fluid
Faulty transmission control module (TCM)
Internal transmission problems
Poor electrical connections
Malfunctioning valve body

Common misdiagnoses

Transmission fluid issues
Faulty transmission control module (TCM)
Shift solenoid A failure
Wiring or connector problems
Transmission valve body issues
Internal transmission damage
Engine control module (ECM) problems
Incorrectly diagnosed sensor failures

Troubleshooting steps

1. Check for Additional Codes

Use an OBD-II scanner to check for any other related trouble codes. Sometimes, multiple codes can provide more context for the issue
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 dark, burnt, or has a burnt smell, consider changing it
5. Examine Wiring and Connectors
6. Inspect the wiring harness and connectors related to the shift solenoid B for any signs of damage, corrosion, or loose connections
7. Repair or replace any damaged wiring or connectors
8. Test the Shift Solenoid
9. Use a multimeter to test the resistance of the shift solenoid B. Compare the readings to the specifications in the vehicle’s service manual
10. If the solenoid is faulty, it may need to be replaced
11. Check for Mechanical Issues
12. Inspect the transmission for any mechanical issues that could affect shifting, such as worn clutches or bands
13. Look for any signs of internal transmission damage
14. Scan for TCM Issues
15. The Transmission Control Module (TCM) may have issues that could cause intermittent solenoid operation. Check for TCM updates or reprogramming needs
16. Perform a Transmission Fluid Flush
17. If the fluid is contaminated, a complete flush may help improve performance and resolve shifting issues
18. Road Test the Vehicle
19. After performing any repairs, take the vehicle for a test drive to see if the issue persists. Pay attention to how the transmission shifts under different conditions
20. Consult a Professional
21. If the problem continues after performing these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis
22. Clear Codes and Monitor
23. After repairs, clear the codes and monitor the vehicle for any reoccurrence of the P078E code. By following these steps, you can systematically diagnose and address the issue related to the P078E 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 dark, burnt, or has a burnt smell, consider changing it

5. Examine Wiring and Connectors

6. Inspect the wiring harness and connectors related to the shift solenoid B for any signs of damage, corrosion, or loose connections

7. Repair or replace any damaged wiring or connectors

8. Test the Shift Solenoid

9. Use a multimeter to test the resistance of the shift solenoid B. Compare the readings to the specifications in the vehicle’s service manual

10. If the solenoid is faulty, it may need to be replaced

11. Check for Mechanical Issues

12. Inspect the transmission for any mechanical issues that could affect shifting, such as worn clutches or bands

13. Look for any signs of internal transmission damage

14. Scan for TCM Issues

15. The Transmission Control Module (TCM) may have issues that could cause intermittent solenoid operation. Check for TCM updates or reprogramming needs

16. Perform a Transmission Fluid Flush

17. If the fluid is contaminated, a complete flush may help improve performance and resolve shifting issues

18. Road Test the Vehicle

19. After performing any repairs, take the vehicle for a test drive to see if the issue persists. Pay attention to how the transmission shifts under different conditions

20. Consult a Professional

21. If the problem continues after performing these steps, it may be best to consult a professional mechanic or transmission specialist for further diagnosis

22. Clear Codes and Monitor

23. After repairs, clear the codes and monitor the vehicle for any reoccurrence of the P078E code. By following these steps, you can systematically diagnose and address the issue related to the P078E code