P27E5

Code

Generic P — Powertrain

Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit Low

Brand: Generic

Type: P — Powertrain

Views: UK: 38 EN: 51 RU: 37

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Page language: EN

Causes

Open or high-resistance wiring in the pump control valve circuit (broken conductor, corrosion)
Poor or corroded connector pins at the pump, valve, fuse/relay, or TCM
Short to ground on the control or feedback circuit
Blown fuse, faulty relay, or loss of supply voltage to the pump/valve
Failed pump motor, solenoid/valve actuator, or internal valve wiring
Low battery voltage or weak charging system while driving the circuit

Symptoms

Transmission warning lamp or MIL illuminated
Reduced transmission performance or limp mode
Delayed or harsh shifts, inability to achieve correct line pressure
No audible pump operation from auxiliary pump when commanded
Transmission overheating or fluid pressure-related complaints
Stored related transmission fault codes

What to check

Read and record freeze-frame and live data with a capable scan tool (pump command, duty cycle, voltage, related temps)
Verify battery voltage and charging system condition at rest and during cranking
Inspect fuses and relays for the pump circuit; test/replace if needed
Visually inspect wiring harness and connectors for damage, corrosion, or water intrusion
Backprobe connector at pump/control valve to measure command and supply voltages with connector mated
Measure resistance of the pump/valve coil (compare to specification) and check continuity to the TCM

Signal parameters

Control command: PWM duty cycle from TCM, typically 0–100% (varies by vehicle)
Expected supply voltage: near battery voltage when powered (~12–14 V) at pump power feed
Control/feedback circuit voltage when inactive: typically 0–1 V (low) or 0–5 V depending on design; when commanded may vary with PWM
Typical coil/actuator resistance (generic): low-ohm range (approx. 2–40 Ω) — check specific vehicle specs
If equipped with feedback sensor, expected feedback signal: 0–5 V or digital signal — consult OEM data

Diagnostic algorithm

Retrieve and record fault codes and freeze-frame data with a scan tool. Note battery voltage and engine/transmission temperatures when the code set.
Visually inspect connectors, wiring, and harness routing for damage, corrosion, or pinched areas between pump/valve and TCM/fuse box.
Verify battery and charging system are healthy. Low battery/charging can cause low circuit voltage faults; charge or load-test battery as needed.
Check related fuses and relays for continuity and correct operation. Replace any blown fuse or suspect relay, then retest.
With ignition on, backprobe the pump/valve connector and measure supply voltage and control signal while commanding the pump via the scan tool. Compare to expected battery voltage and commanded duty.
Measure resistance of the pump/valve coil (with connector disconnected) and check continuity to the TCM pin to rule out open circuits. Compare to manufacturer spec.
Check for a short to ground between the control/feedback wires and chassis using an ohmmeter (with battery disconnected) or a dedicated short-check tool.
If wiring and connectors are good, apply controlled bench power (or command from scan tool if supported) to the pump/valve to confirm operation. Listen/feel for pump motor or valve movement.
If pump/valve fails the functional test, replace the component. If component tests good but circuit still reads low, inspect and repair wiring or replace the TCM only after ruling out all wiring and power/ground issues.
Clear codes and perform a road/operational test to confirm fix. Re-scan after test to verify code does not return.

Likely causes

Corroded/loose connector at the pump or control valve
Open or pinched wiring harness to the pump/valve
Failed pump/valve actuator (internal coil or motor open)
Blown fuse or failed relay supplying pump power
Short to ground on the control/feedback lead

Fault status

⚠️ Status

P27E5 — Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit Low: Control circuit voltage or signal is below the expected threshold. Possible causes include open or shorted wiring, poor connector, blown fuse/failed relay, failed pump/valve actuator, low battery, or TCM fault.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours