What it means
The control module detects a low electrical level in the shift solenoid H control circuit.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Shift solenoid H is an electrically operated valve used to control transmission fluid flow during shifting. This code sets when the control module detects a lower electrical level than expected in the solenoid H control circuit, often because the wire is shorted to ground or the coil is shorted.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in coil
- Connector pins corroded - high contact resistance
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Save freeze-frame data and check live transmission data for solenoid H commands and shift symptoms that coincide with the fault.
- Inspect the solenoid H connector and harness for rubbed-through insulation, fluid intrusion, corrosion, or damaged terminals that could ground the circuit.
- Use the wiring diagram and manufacturer's procedure to check the solenoid H control wire for a short to ground.
- Test the solenoid H coil and circuit for a short or resistance outside the manufacturer's specification.
- If the wiring and solenoid pass, test the control module output and grounds using the manufacturer's procedure.
Common fixes
- Repair the solenoid H control wire if it is shorted to ground.
- Clean or repair corroded or damaged terminals at the solenoid H connector.
- Replace shift solenoid H if its coil tests shorted or outside specification.
- Repair the solenoid H harness if testing finds an intermittent or high-resistance connection.
- Repair or replace the control module only if testing confirms it is causing the low circuit condition.
Can I keep driving?
Avoid towing or hard acceleration, and stop driving if the transmission slips badly or cannot select gears reliably. A low solenoid H circuit can disrupt shifting, and continued slipping may cause further damage.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.