P27CD: Pressure Control Solenoid R Control Circuit/Open

What it means

The control circuit for pressure control solenoid R is reporting an open condition.

At a glance

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

How it works

Pressure control solenoid R is an electrically operated valve used to regulate transmission hydraulic pressure. P27CD sets when the module detects an open circuit in the solenoid R control path, such as a broken wire, disconnected terminal, or open coil.

Common causes

Most likely first.

1. Open in solenoid control wire
2. Open solenoid coil
3. Pin pushed back out of connector body

Symptoms

• Transmission warning light may illuminate
• Harsh or delayed shifting
• Transmission may enter limp mode

How to diagnose it

1. Record freeze-frame data and check for related solenoid R codes to understand when the open-circuit fault was detected.
2. Inspect the solenoid R connector for a disconnected plug, a pushed-back pin, corrosion, or a terminal that does not grip.
3. Trace the solenoid R control wire for breaks, damaged insulation, or a disconnected section using the vehicle wiring diagram.
4. Measure solenoid R coil resistance and compare it with the manufacturer's specification to determine whether the coil is open.
5. Check control-wire continuity from the module connector to solenoid R, isolating the circuit as directed by the wiring diagram.
6. If the connector, coil, and wire pass, check the module-side connection and control circuit for an open before suspecting a module fault.

Common fixes

• Seat the solenoid R connector and restore contact with any pushed-back terminal.
• Repair or replace the broken solenoid R control wire.
• Replace solenoid R if its coil measures open against the manufacturer's specification.
• Repair an open at the module connector or control circuit if testing locates it there.

Can I keep driving?

Avoid towing or demanding driving if shifts are harsh, delayed, or the transmission enters limp mode. An open solenoid R circuit can disrupt pressure control and cause worsening shift problems; stop if the transmission slips or cannot select gears reliably.