P2E48

Code

Generic P — Powertrain

Hybrid/EV Electronics Coolant Pump B Overspeed

Brand: Generic

Type: P — Powertrain

Views: UK: 17 EN: 34 RU: 20

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Page language: EN

Causes

Pump B speed above allowed limit (mechanical or electrical)
Faulty pump speed sensor or sensor signal (false high reading)
Motor driver or inverter output fault (stuck-on, uncontrolled drive)
Wiring harness or connector short/open causing incorrect feedback or drive
Controller software fault or calibration error
Mechanical decoupling or reduced load on pump allowing overspeed

Symptoms

Malfunction indicator lamp (MIL) or hybrid system warning illuminated
Logged P2E48 in diagnostic trouble codes list
Unusually high pump noise, whining, or vibration
Reduced cooling system performance or unexpected thermal warnings
Erratic pump speed readings on scan tool (very high RPM values)
Possible limp-home mode or reduced vehicle performance depending on system design

What to check

Read and record freeze frame and all stored/active codes with a professional scan tool
Check for related codes (pump A, pump driver, speed sensor, CAN communication)
Visually inspect wiring and connectors at Pump B and the control module for damage, corrosion, or pin push-out
Verify vehicle battery/auxiliary supply voltages are within specification
Listen for abnormal pump noise during operation (with appropriate HV/12V safety)
Check for recent software/ECU updates or service bulletins related to pump control

Signal parameters

Expected pump speed (typical) — nominal range depends on design; example: 1,000–7,000 RPM under normal conditions (refer to manufacturer spec)
Overspeed detection threshold — controller-defined (example: 7,500–9,000 RPM); DTC set when feedback > threshold
Motor supply voltage — often 12 Vdc or high-voltage pack depending on vehicle; verify actual system spec
PWM drive frequency — typically hundreds Hz to several kHz; compare commanded duty cycle vs measured
Speed sensor output — tachometer/Hall pulse signal; expected pulse frequency proportional to RPM (e.g., X pulses per revolution), signal amplitude per spec (0–5 V or open-collector)
Typical operating current — varies by design; abnormally low current with high RPM can indicate reduced load or slipping coupling

Diagnostic algorithm

Retrieve freeze-frame data and all related DTCs; note operating conditions (SOC, vehicle speed, temperature, battery voltage).
Confirm whether the code is current, pending, or historic; attempt to reproduce with the appropriate operating conditions.
Visually inspect harnesses and connectors for Pump B and its controller. Repair any damaged wiring or corroded connectors before further testing.
With the proper safety procedures (isolate high-voltage systems if applicable), start the system and monitor pump command (PWM/duty cycle), pump supply voltage, and speed sensor output with an oscilloscope or lab-quality scan tool.
Compare commanded speed (controller output) to measured speed (sensor). If commanded duty is low but measured speed is high, suspect sensor or wiring causing false high feedback. If commanded duty is high and speed is high, suspect driver/motor or mechanical issue.
Check motor current draw: a low current with high speed may indicate mechanical decoupling; excessive current may indicate binding or electrical fault.
Backprobe the sensor harness and measure pulse frequency/amplitude at known RPMs; confirm pulse-per-revolution calibration with service data.
If sensor signal is noisy or absent, repair or replace sensor and retest. If driver output is abnormal (stuck-on or shorted), inspect driver electronics and power stage; consider module replacement per service manual.
Review technical service bulletins and confirm correct software/calibration levels for pump controller; apply updates if available.
After repairs, clear codes and perform a full functional test over the conditions that originally set the code to confirm resolution.

Likely causes

Failed or noisy speed sensor producing spurious high pulses
Power stage (MOSFET/transistor) in pump driver stuck on or damaged
Wiring short between motor control output and battery or ground
Connector corrosion or intermittent connection at pump or control module
Controller receiving incorrect parameter (bad calibration, software bug)
Impeller worn/damaged or mechanically unloaded causing speed runaway

Fault status

⚠️ Status

Stored when Coolant Pump B speed feedback exceeds the controller’s allowed maximum (overspeed) or when the control module detects a persistent mismatch between commanded and actual pump speed. Code may be intermittent or persistent depending on cause.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.0-3.5 hours