What it means
The electric/auxiliary transmission fluid pump control valve circuit is reporting a low electrical condition.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The electric or auxiliary transmission pump control valve changes hydraulic flow or pressure under module control. The module monitors the valve's electrical circuit and sets P27E5 when the circuit reads lower than expected, often because its control wire is grounded, the coil is shorted, or a connector has poor contact.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in valve coil
- 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
- Record freeze-frame data and examine live data for the pump control-valve command and pressure response when the low-circuit fault occurs.
- Inspect the valve connector and harness for chafing, pin damage, corrosion, fluid intrusion, or a control wire touching ground.
- With the circuit isolated as the manufacturer specifies, check the control wire for a short to ground and damaged insulation.
- Measure control-valve coil resistance against the manufacturer's specification to check for an internal short.
- If the wire and coil pass, test the module output and connector terminals using the manufacturer's diagnostic procedure.
Common fixes
- Clean and secure corroded or loose valve connector terminals.
- Repair the control wire where it is grounded or damaged.
- Replace the control valve if its coil is shorted or outside specification.
- Repair the module driver only after confirming the valve and wiring are sound.
Can I keep driving?
Avoid driving if shifts slip, become harsh or delayed, or the transmission enters limp mode, since incorrect pump control can lead to further transmission damage. If it cannot shift or hold a gear safely, stop driving and arrange assistance.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.