P27EA: Transmission Range Control B Circuit High
What to do
Always apply the parking brake when you park — do not rely on P. With range actuation faulty, the car may not fully engage or confirm the park pawl, and a car held only by a pawl it cannot verify is a car that can roll. Expect refused or delayed range changes, and have it repaired promptly rather than working around it.
What this code means
Transmission range control circuit B is reading high.
A circuit reading high usually means a short to voltage or an open circuit leaving the line pulled up — the command level never changes at the pump, however hard the module drives it.
Shift-by-wire replaced the cable from your hand to the gearbox with a message, and this circuit carries out the message. The selector is just a switch; at the gearbox, an actuator physically moves the range mechanism between park, reverse, neutral and drive. This family covers the B channel of that actuation — designs split the work across two circuits, or carry the second as redundancy for the first.
When actuation fails, the concern is not the gear you are in but the one you cannot reach — park. Park is a mechanical pawl that must be driven in and out, and a range actuator fault can leave the module unable to engage it, unable to confirm it, or unwilling to release it. The module usually responds cautiously: refusing changes, holding the current range, or parking itself electrically and calling for attention.
Prove the circuit before condemning the actuator, and check the mechanism before either. A seized or obstructed park mechanism raises the current every shift costs until the circuit trips its limits — the electrical code can be the mechanical fault's messenger.
Likely causes
Start here
- Faulty transmission range selector motor · specialist
- Corroded or loose connector · specialist
- Damaged wiring harness · specialist
Less common
- Seized or obstructed park mechanism · specialist
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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