Voltage on the second auxiliary transmission fluid pump control line is above the expected window. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Medium severity. Can I keep driving?Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
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
Most likely causes
- Control wire shorted to B+
- Open motor winding
- Connector pins corroded - high contact resistance
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
What each character of P27A5 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 7: Transmission
- A5: Specific fault in that system
Frequently asked questions
Can I keep driving with code P27A5?
Drive gently to a repair shop. If it slips, you hear clunks, or it loses its gears, do not keep driving.
What causes code P27A5?
The most common causes are: control wire shorted to B+; open motor winding; connector pins corroded - high contact resistance.
Related codes
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.