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Home / Codes / P0788
DTC code page

P0788: Shift/Timing Solenoid A Circuit High

Quick answer: The controller sees the shift/timing solenoid A circuit voltage higher than expected.

Drivers also search this fault as shift timing solenoid A circuit high, P0788 high input, solenoid A circuit high voltage.

Severity: high Family: powertrain Related paths: 9
Meaning

What P0788 usually means

P0788 is the high-circuit counterpart to P0787. On most transmissions that points toward an open circuit, excessive resistance, an unplugged connector, or a driver path that is not pulling the circuit where it should. The vehicle can still feel just as bad as with a low-circuit fault—harsh shifts, limp mode, no upshift—but the code wording gives the diagnostic order away. Before blaming the valve body or internal clutches, prove whether the module is simply trying to command a solenoid through a broken electrical path.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Look for any recent transmission service or connector disturbance, because unplugged or poorly seated connections are common here.
  • Check whether the complaint appeared all at once, which often fits an open circuit or broken connection.
  • See if other high-circuit codes are present, suggesting a shared connector or internal harness issue.
Driving risk

Can you keep driving?

P0788 commonly causes backup-gear operation or harsh shifting because the controller no longer trusts the solenoid circuit. Driving should be limited if normal shifts are gone.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Symptoms

Common symptoms

Likely causes

Common causes behind this code

  • Open circuit in the shift/timing solenoid A path
  • High resistance from corroded or loose connector terminals
  • Unplugged or damaged transmission case connector
  • Failed solenoid A coil with an open winding
  • Control-module driver fault

Cause phrases often tied to this code: open shift timing solenoid A circuit, high resistance solenoid wiring, unplugged connector, failed solenoid A coil open, module driver issue.

Diagnostic order

Suggested workflow

  1. Read freeze-frame and companion codes before clearing anything.
  2. Measure voltage, continuity, and resistance on the solenoid A circuit and compare with service specifications.
  3. Inspect case connector fit, terminal tension, corrosion, and internal harness routing.
  4. If the harness is healthy, test the solenoid coil and the module driver path for an open or weak response.
  5. After repair, verify normal shift operation returns and the code does not reset.
Avoid guesswork

Common mistakes

  • Treating P0788 like a generic bad-transmission code instead of an electrical path problem.
  • Skipping terminal-fit checks because the connector appears plugged in.
  • Clearing the code before capturing whether it was a true open-circuit event.
Repair path

Practical fix guidance

  • Handle P0788 as an open-or-high-resistance diagnosis first and a hydraulic problem second.
  • If multiple solenoid high-circuit faults show up together, chase the shared connector or internal harness before individual parts.
  • Do final verification with a full hot road test so you know the command path stays stable.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0788

Useful when the driver knows the wording but not the exact DTC yet.

  • shift timing solenoid A circuit high
  • P0788 high input
  • solenoid A circuit high voltage
Related search intent

Queries this page can answer naturally

  • P0788 code meaning
  • what does P0788 mean
  • shift timing solenoid A circuit high
  • P0788 transmission code
FAQ

Quick questions about P0788

What does circuit high mean for P0788?

It usually means the controller sees an open circuit or more resistance than expected in the solenoid path.

Can a loose connector cause P0788?

Yes. A partially seated or corroded connector is one of the most common reasons a high-circuit code appears.

Does P0788 prove the solenoid itself is bad?

No. The harness, connector, and driver path all need to be checked before the solenoid is blamed.