P0787: Shift/timing solenoid circuit low: the computer sees a low signal on the solenoid circuit
Shift/timing solenoid low
Severity: Severity not verified — if the car runs badly, have it inspected
The sources define the code and list causes but do not say whether you can keep driving.
P0787 in short
P0787 is the shift/timing solenoid low code: the transmission or engine computer flagged a problem with the solenoid circuit. TroubleCodes.net points to the wiring, the solenoid itself or the control module. A scan tool that reads the transmission module is needed to tell which.
The Delaware DMV code list titles P0787 as Shift/Timing Solenoid Low. TroubleCodes.net gives the same definition and lists wiring, the solenoid and the control module as the probable causes.
TroubleCodes.net notes a basic OBD-II adapter shows the code but not the transmission module or bidirectional tests, which are what show which part has failed.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Wiring short to ground
Common general cause- Why it ranks here
- TroubleCodes.net names a wiring short to ground as the first probable cause of a low reading.
- What would change this
- Rises if the harness or connector is damaged. Falls if the circuit tests good.
Cause 2: Faulty shift/timing solenoid
Common general cause- Why it ranks here
- TroubleCodes.net lists the shift/timing solenoid itself as a probable cause.
- What would change this
- Rises if the solenoid fails a bidirectional or resistance test. Falls if it responds correctly.
Cause 3: Engine, powertrain or transmission control module fault
Possible — needs testing- Why it ranks here
- TroubleCodes.net lists the control module, but only after the wiring and solenoid are cleared.
- What would change this
- Rises only after wiring and solenoid both test good.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read all codes and freeze-frame data from the engine and transmission modules with a scan tool before clearing anything.
IfOther solenoid or shift codes are stored
It meansDiagnose them together.
IfP0787 is alone
It meansInspect the wiring.
Step 2: Inspect the transmission wiring and connectors for damage, corrosion and a short.
IfDamage or corrosion is found
It meansRepair it and retest.
IfWiring is sound
It meansHave the solenoid tested.
Step 3: Have a shop command the solenoid with a bidirectional scan tool and check its circuit.
Warning:Reaching the solenoid can mean dropping the pan, which releases hot fluid, and the vehicle must be safely supported. Leave it to a shop.
IfThe solenoid fails the test
It meansSolenoid fault.
IfSolenoid and wiring both pass
It meansSuspect the control module.
Points to: Engine, powertrain or transmission control module fault
Symptoms
- Check engine light
- Shifting problems are possible, but TroubleCodes.net lists no specific symptoms for this code
How to fix
Step 1: Do not clear the code before the transmission module has been read.
Parts and cost context
- Transmission control module (TCM):A control module fault ranks last; confirm wiring and solenoid first.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
We don't have reviewed vehicle-specific evidence for P0787 yet. The causes and tests above apply across vehicles.
Related codes
P0787 questions
What does P0787 mean?
A shift/timing solenoid circuit problem (low).
Can I drive with P0787?
We found no source that says. Have the transmission module read and inspected.
Sources and review
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error