What it means
Shift timing solenoid B control circuit reads stuck high — short to battery voltage or open coil.
At a glance
- Usually lights the check-engine light
How it works
Shift timing solenoid B is controlled by the TCM through a dedicated circuit. This high-circuit code sets when the monitored control signal remains above the expected range, which can happen with an open coil or wire, a short to voltage, or a driver fault.
Common causes
Most likely first.
- Open circuit in the solenoid wiring or coil
- Short to voltage in the control wiring
- Shift Timing Solenoid B coil failure
- Damaged connector or transmission control module driver
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 data for solenoid B command and circuit status when the high condition appears.
- Inspect the solenoid B connector and harness for a disconnected terminal, broken wire, corrosion, or insulation damage that could expose the circuit to voltage.
- Test the solenoid B circuit for an open and for a short to voltage, following the manufacturer's procedure.
- Measure the solenoid B coil and compare it with the manufacturer's specification to identify an open coil.
- If the wiring and coil pass, test the TCM driver according to the manufacturer's diagnostic steps.
Common fixes
- Reconnect or repair an open solenoid B wire.
- Repair wiring shorted to voltage and secure it away from other powered circuits.
- Clean or replace damaged connector terminals.
- Replace shift timing solenoid B if its coil is open or out of specification.
- Repair the TCM driver only after confirming the solenoid and wiring are sound.
Can I keep driving?
Keep driving to a minimum and avoid towing or hard acceleration because the transmission may lose proper control of shifts. Stop if you notice slipping, severe shift impacts, or loss of gears.
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.