P2E45

Code

Generic P — Powertrain

Hybrid/EV Electronics Coolant Pump B Enable Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 15 EN: 25 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in pump enable/control wiring (broken conductor, chafing, corrosion)
Poor connector contact at pump or control module (corrosion, bent pins, loose terminal)
Blown fuse or failed relay supplying pump power or enable circuit
Faulty coolant pump (motor or internal electronics)
Faulty powertrain control module (PCU/BCM/EV control module) driver or software
Low battery/high-voltage supply or intermittent supply to pump

Symptoms

HV/EV system warning or coolant pump warning lamp illuminated
Reduced cooling of power electronics or battery (temperature rise or derate)
Coolant pump B does not run when commanded
Thermal management related limp-home mode or reduced performance
Stored DTC(s) related to thermal management or pump circuits

What to check

Read freeze-frame and live data from EV/Powertrain modules; note when DTC set
Check for other related DTCs in EV/PCM/BCM and battery management module
Visual inspection of pump, wiring harness, connectors, mounting and coolant level
Verify fuses and relays for pump power and control circuits
Measure supply voltage and ground at the pump connector with key ON and when pump commanded
Check continuity and resistance of the enable/control conductor(s) between module and pump

Signal parameters

Battery / high-voltage bus voltage (vehicle dependent) — pump supply voltage when enabled
Enable/control signal voltage at pump connector (0 V, battery voltage or PWM) — expected when commanded
PWM frequency and duty cycle of enable signal (if PWM controlled) — consult vehicle spec
Pump motor current draw when running (should be within spec)
Resistance (ohms) of pump motor winding or internal electronics
Ground continuity / voltage drop on ground circuit

Diagnostic algorithm

Retrieve all related codes and freeze frame data from all modules. Note conditions when fault set (ignition state, temperature, vehicle mode).
Perform visual inspection: connectors at Pump B and control module, harness for damage, coolant level and pump mounting.
Verify fuses and relays for the pump power and control circuits; replace any blown items and retest.
With the vehicle in a safe state (park/neutral, service mode if required), command the pump ON via scanner and observe live data: check supply voltage at pump connector and whether an enable signal is present.
If no enable signal from control module, back-probe the module output and check for expected voltage or PWM when commanded. If module does not command, check upstream inputs and software updates.
If enable signal is present but pump does not run, measure pump supply voltage and ground under command and measure pump current. If supply present and current low/zero, remove and bench-test pump (only for LV pumps; follow HV safety procedures for high-voltage pumps).
Check wiring continuity and resistance between control module and pump for open/short/high resistance. Repair any damaged wiring or poor connections.
If wiring and pump test good and module output remains abnormal, consider control module driver failure or software; verify with module bench test or replace/ reprogram per factory procedure.
After repairs, clear codes and perform functional test under the conditions that caused the DTC; monitor temperatures and confirm no recurrence.

Likely causes

Loose/corroded connector at pump or control module
Open/shorted wiring between control module and pump
Failed pump motor or internal pump electronics
Blown fuse or defective relay in pump power/enable circuit
Control module output driver fault or software error

Fault status

⚠️ Status

Electronics Coolant Pump B enable/control circuit fault detected — expected enable signal missing or abnormal. Cooling pump may not run when commanded.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours