P27E6

Code

Generic P — Powertrain

Electric/Auxiliary Transmission Fluid Pump Control Valve Circuit High

Brand: Generic

Type: P — Powertrain

Views: UK: 36 EN: 51 RU: 41

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Causes

Short to battery voltage on the pump control valve wiring
Faulty pump control valve (solenoid) with internal short
Damaged wiring harness (chafing, pinched, corroded connector)
Poor or missing ground related to the pump/TCM
Failed TCM/ECM driver output stage
Blown or incorrect fuse/relay feeding the circuit

Symptoms

Transmission warning lamp or MIL illuminated
Transmission may default to limp/backup mode or have restricted functionality
Unusual transmission behavior: hard shifts, delayed engagement, or no engagement
Auxiliary pump may run continuously or not run when commanded
Possible noise from pump or no pump operation
Stored related transmission codes

What to check

Retrieve freeze-frame and full DTC list with a scan tool; note drive conditions and related codes
Visual inspection of pump harness and connector for damage, corrosion, moisture or pinched wires
Check fuses and relays for the transmission pump circuit
With key ON (engine off) backprobe connector: measure voltage on control pin and reference/ground
Measure solenoid coil resistance at connector with connector disconnected (compare to spec)
Check for short to battery: measure resistance from control circuit to battery + with ignition off

Signal parameters

Expected inactive/control-off voltage: near 0 V (depending on design) — high reading indicates short to battery
Commanded signal: typically a switched/PWM driver varying between 0 and battery voltage (0–12V) with variable duty cycle
Typical solenoid coil resistance (generic): approx. 2–40 ohms (manufacturer-specific — consult service data)
Typical operating current: tenths to several amps depending on pump/solenoid design (check manufacturer spec)
PWM frequency: varies by manufacturer (tens to several hundred Hz) — check vehicle service data for exact value

Diagnostic algorithm

Read and record all codes and freeze-frame data. Note any related transmission or powertrain codes.
Visually inspect harness and connectors from TCM to pump. Repair obvious physical damage, corrosion, or water ingress.
Check and verify fuse(s) and relay(s) that feed the pump and control circuits. Replace if faulty.
With ignition OFF, disconnect pump connector and measure solenoid coil resistance. Compare to spec. A very low resistance suggests internal short.
With connector disconnected, measure resistance from control pin to battery + and to chassis ground to detect short to voltage/ground.
Reconnect and backprobe the control circuit. With key ON and engine OFF, observe resting voltage. Then command the pump ON with a scan tool and observe voltage/current/PWM. High resting voltage or stuck-high indicates short to power or failed driver.
If wiring and pump check OK, test for intermittent faults by gently flexing harness while observing the circuit signal and code behavior.
If tests point to the pump solenoid, replace the pump or solenoid assembly and retest. If wiring and pump are good, suspect TCM output driver failure—verify by comparing to another known-good circuit or performing TCM bench/diagnostic procedures per service manual.
After repairs, clear codes and perform a road test or activation tests to confirm the fault does not return.
Safety note: when performing live circuit tests, follow vehicle-specific safety procedures and disconnect battery where appropriate before repairs.