|Trouble Code||Fault Location||Probable Cause|
|P0768||Shift solenoid (SS) D -electrical||Wiring, shift solenoid, ECM/PCM!TCM|
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What Does Code P0768 Mean?
Shift solenoid are responsible for shifting your transmission’s gears. It uses pulse width modulated solenoid to control fluid pressure/flow. Your transmission may have multiple shift solenoids. They are part of the valve body in the transmission. The transmission control module TCM monitors a combination of sensors within the system (speed sensors, throttle position sensor TPS, etc..) in conjunction with the powertrain control module and other sensors to determine the shifting of the transmission. It modifies the signal to Shift solenoid to adjust accordingly. Given that the code indicates electrical, a good place to start with, is on the electrical side of things. Accessing the shift solenoids in the transmission can be very invasive, better left to a transmission repair facility. The PCM and TCM compares and monitors all the sensors involved with the system and if they detect anything out of specified values they throw the light on the instrument cluster. Transmission repairs can get expensive so you will want to make sure to cover the basics before jumping to any conclusions.
What are the common causes of code P0768 ?
- Low transmission fluid level
- Dirty transmission fluid
- Transmission control module
- Shift solenoid defective
- Shift solenoid circuit open/short
- Bad grounds
- Corroded connections or pins
- Wring issue (corrosion, chafed, melted)
What are the symptoms of code P0768 ?
- Not shifting
- Drivability issues
- Harsh shifts
- Erratic shifts
- High engine RPMs
How do you troubleshoot code P0768 ?
BASIC STEP #1:
Check your fluid. Verify when the last fluid change was done and refer to service manual for service intervals. If beyond interval, you should replace the oil, if not, verify level and condition. If you do replace the fluid in the transmission and you will have the oil pan off, it would be a good idea to check the shift solenoid circuit if accessible. Refer to service manual and other troubleshooting steps.
NOTE: ALWAYS use specific automatic transmission fluid for make/model. This step is important in preventing any serious damage to transmission internals. A mistake here could potentially cost you LOTS of $$.
BASIC STEP #2:
Check shift solenoid circuit. Refer to service manual for connector locations. You may need to unplug several connectors in order to check circuit integrity. Make sure to disconnect battery before proceeding. Depending on the particular system layout you may need to to check circuit between solenoid to transmission control module and between powertrain control module and TCM. Make sure to perform basic circuit testing (i.e: open, short to power or ground, high resistance). Refer to manual for specific desired values. Perform necessary repairs and test drive. If everything checked out and code is still active, proceed to next step.
BASIC STEP #2:
Check shift solenoid. This procedure varies between manufacturer and specific system operation but generally speaking, you need a OBD2 scanner with monitoring capabilities to verify solenoid functionality. You may be able to turn solenoid on/off and monitor status on scanner to determine solenoid performance. Refer to service manual for procedure. Keep in mind you may even need to use a manufacturer specific OBD scanner to access these functionality tests. Sometimes you need to bring vehicle to repair facility to get accurate diagnosis.
BASIC STEP #3:
Replace shift solenoid. If you’ve referred to service manual and you are confident in your capabilities, you may be able to replace solenoid without too much trouble. Depending on the price of shift solenoid and accessibility, it may be worth a try but keep in mind you may be guessing at this point. Make sure to replace with new fluid if you haven’t already , to prevent any damage to new sensor. It is imperative to keep sensor clean of debris before installing to prevent any malfunctions.
BASIC STEP #4:
If you’ve replaced sensor, the fluid and the circuits check out, it’s time to check PCM and TCM operation. Refer to specific manufacturer for procedures. This may be the time to bring to a reputable transmission repair facility to diagnose and repair issue with transmission. Make sure to let them know if you’ve replaced fluid , to prevent any mix up. Good luck!
Codes Related to P0768
- P0764 Shift solenoid (SS) C -circuit intermittent
- P0765 Shift solenoid (SS) D -circuit malfunction
- P0766 Shift solenoid (SS) D -performance or stuck off
- P0767 Shift solenoid (SS) D -stuck on
- P0769 Shift solenoid (SS) D -circuit intermittent
- P0770 Shift solenoid (SS) E -circuit malfunction
- P0771 Shift solenoid (SS) E -performance or stuck off