P090D: Clutch B Actuator Control Circuit High

What it means

The clutch B actuator control circuit reports a control circuit high condition. Clutch B engagement cannot be commanded reliably.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

The TCM drives the Clutch B actuator through a control circuit and checks the circuit's electrical level while commanding the clutch. This code sets when the circuit reads higher than expected, which can happen if the control wire is shorted to B+, the actuator coil is open, or a corroded connection disrupts the circuit.

Common causes

Most likely first.

1. Control wire shorted to B+
2. Open actuator coil
3. 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

1. Record freeze-frame data and review live Clutch B commands to see when the circuit-high fault occurs.
2. Inspect the actuator connector and control wiring for corrosion, damage, poor seating, or contact with a power wire.
3. With the circuit isolated according to the manufacturer's procedure, test the control wire for a short to B+.
4. Check the Clutch B actuator coil for continuity and compare the result with the manufacturer's specification.
5. If the wire and coil test correctly, inspect connector contact resistance and the TCM-side circuit using the manufacturer's procedure.

Common fixes

• Repair a control wire shorted to B+.
• Restore damaged or corroded connector terminals.
• Repair an open or damaged section of Clutch B control wiring.
• Replace the actuator if its coil is confirmed open.

Can I keep driving?

Limit driving if Clutch B engagement is unreliable, and stop if the transmission slips, loses drive, or cannot select a safe gear. An uncontrolled or unavailable clutch can cause missed shifts and additional transmission damage.