P0787: Shift/Timing Solenoid Low DTC Trouble Code

If the vehicle has a P0787 diagnostic trouble code, it means that there is an abnormally low voltage signal coming from the shift timing solenoid. If this is the case, then the ECU may not be able to determine what gear the transmission is in.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

How Serious is the Code?

The P0787 DTC is meant to let you know that the computer may not be fully in command of the transmission’s hydraulic system, which can lead to further transmission problems and drivability concerns.

Symptoms

Symptoms of a P0787 include:

• Check engine light
• Transmission slipping
• Limp mode
• Erratic, delayed or harsh shifts
• Transmission gets stuck in a gear
• Vehicle won’t move when in gear
• Transmission overheats
• Lower MPG

Causes

• Insufficient transmission fluid
• Dirty transmission fluid / filter
• Frayed wiring
• Damaged connectors
• Failing shift timing solenoid
• Internal pressure problems
• ECU or TCM failure

How to Diagnose the Code?

The first thing that a mechanic should look at when diagnosing a solenoid related fault code is the level and condition of the transmission fluid. If it’s excessively dirty, or metal shavings are present, then the transmission could have serious internal damage. Regular maintenance is an easy way to extend the life of your transmission. Failing to have your transmission serviced on time, will result in catastrophic wear to internal components, which include the solenoids. It is possible to flush the transmission and clear blocked hydraulic passages. However, this may only be a temporary fix if damage has already been done to the valve body, clutches or seals.

If the transmission fluid is clean and there are no leaks, then the wiring harness and connectors should be carefully examined for signs of damage and corrosion. If no issues are found, then the shift/timing solenoid should be tested directly following the manufacturers recommended test procedure. If the solenoid functions properly, then other components like the valve body could be at fault.

Common Mistakes When Diagnosing

Often times, a shift timing solenoid OD2 trouble code can be caused by in an electrical short, or a blocked hydraulic passage.

What Repairs Will Fix P0787?

• Changing the transmission fluid and filter
• Replace faulty shift timing solenoid
• Perform transmission flush to clean passages
• Cleaning corrosion from connectors
• Repairing or replacing wiring
• Flash or replace PCM/TCM

Related Codes

P0785 – Shift/Timing Solenoid

P0786 – Shift/Timing Solenoid Range/Performance

P0788 – Shift/Timing Solenoid High

P0789 – Shift/Timing Solenoid Intermittent

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

Full Transmission DTC Codes Table