P0788 moderate

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.

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Keep driving?: Short distances only
DIY difficulty: hard
Estimated cost: $150 - $600 (parts and labor)

Check Your Fluid First

ANCEL AD310 OBD-II Scanner

Read and clear transmission codes. Many trans codes are caused by low or burnt fluid -- check level and color before assuming the worst.

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Read Transmission Codes

LAUNCH CRP123X (Reads All Systems)

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

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

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.