Shift Timing Solenoid High
The P0788 code means the vehicle's onboard diagnostic system has detected: Shift Timing Solenoid High. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $600 (parts and labor)
Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.
Basic scanners only read engine codes. This reads transmission, ABS, and airbag too.
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Common Symptoms
- Check Engine Light illuminated
- Early or harsh shifts
- Transmission shifts at wrong RPM
- Increased fuel consumption
Probable Causes (Ranked by Likelihood)
- Open timing solenoid circuit Very High
- Open ground wire to timing solenoid High
- Failed timing solenoid coil (open) Moderate
- TCM driver circuit fault Low
Frequently Asked Questions
Can I drive with code P0788?
Drive short distances only. Shift malfunction codes indicate the transmission is not shifting correctly, which can cause further damage.
What does P0788 mean?
Shift Timing Solenoid High. This means the TCM has detected that a shift event is not occurring as expected. The cause can range from a faulty solenoid to internal transmission wear.
Will a transmission flush fix P0788?
A fluid flush alone rarely fixes shift malfunction codes. However, if the fluid is contaminated, a flush combined with solenoid replacement may resolve the issue. Never flush a transmission with heavily burnt fluid, as it can dislodge debris and cause further damage.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Measure timing solenoid resistance -- OL reading confirms open circuit
-
Check ground wire continuity
-
Inspect connector for disconnection
-
Check wiring from TCM to solenoid for breaks
-
Replace solenoid if coil is open
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2003-2015 Mitsubishi Galant
- 2004-2016 Hyundai Tucson
- 2005-2017 Kia Sorento
- 2002-2014 Subaru Outback
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