P27D0: Pressure Control Solenoid R Control Circuit High

What it means

The control circuit for pressure control solenoid R is reporting a high electrical 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 that helps regulate transmission hydraulic pressure. P27D0 sets when the module detects a high electrical condition in its control circuit, which may result from a short to battery voltage, an open coil, or excessive resistance at a connector.

Common causes

Most likely first.

1. Control wire shorted to B+
2. Open solenoid coil
3. Connector pins corroded - high contact resistance

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 identify when the high circuit condition occurred.
2. Inspect the solenoid R harness for damage that could let the control wire contact battery voltage, and check the connector for corrosion or loose terminals.
3. Measure solenoid R coil resistance against the manufacturer's specification to identify an open coil.
4. With the circuit tested as directed by the wiring diagram, check the control wire for a short to battery voltage.
5. Check connector contact and control-wire continuity for excessive resistance or an open between solenoid R and the module.
6. If the coil, connector, and wiring pass, investigate the module-side control circuit using vehicle-specific diagnostic information.

Common fixes

• Clean or repair corroded or loose contacts at the solenoid R connector.
• Repair wiring that is shorted to battery voltage or has an open connection.
• Replace solenoid R if its coil is open or outside the manufacturer's specification.
• Repair a confirmed fault in the module-side control circuit.

Can I keep driving?

Avoid towing or hard acceleration if shifting is harsh or delayed, and do not continue driving if the transmission slips or enters limp mode. The high circuit condition can prevent proper pressure control and lead to worsening shift problems or transmission damage.