Shift Solenoid A Stuck On
The transmission solenoid is stuck in the 'on' position.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
Inside the transmission, there's a shift solenoid that controls when to change gears. If it gets stuck on, the vehicle won't shift gears properly, causing poor performance or it may stay in one gear.
What the computer is actually seeing
The Transmission Control Module (TCM) detects that the voltage signal from the shift solenoid A is constantly high (typically above 5 volts when it should be 0 volts when off).
What a healthy reading looks like
Normal operation should show 0 volts when off and around 12 volts when activated. Should see fluctuating duty cycle from 0% to 100% when functioning correctly.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check transmission fluid level: should be between the marks on the dipstick. If low, fill and recheck the code.
- 2Inspect wiring and connector for the shift solenoid A for any signs of damage or corrosion. Repair if necessary.
- 3Test the shift solenoid A by measuring resistance with a multimeter; it should typically be between 10-30 ohms. If out of spec, replace the solenoid.
- 4Check the TCM for any stored codes or damage. If it has other related codes, further diagnostics are required.
- 5If everything checks out but the code persists, the TCM may need to be replaced.
Common causes
- Faulty shift solenoid A
- Wiring issues (short or open circuit)
- Bad Transmission Control Module (TCM)
- Low transmission fluid level or dirty fluid
- Internal transmission issues.
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not ideal; it can cause poor shifting or stick in one gear, impacting drivability. Fix it soon.
Will the code come back after clearing?
If the underlying issue isn't fixed, it will likely return once the vehicle is driven.
Why does this code often appear with others?
Related solenoids or components can fail together, leading to multiple codes being triggered.
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