Powertrain, generic (extended)

P2E7B Drive Motor A Excitation Current Sensor Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2E7B is the general circuit fault of the measuring element for the DC field current in the rotor of drive motor A. It exists only in electrically excited synchronous motors, whose rotor field comes from a winding, as in Renault's Megane E-Tech, Nissan's Ariya and BMW's fifth-generation eDrive. The controller stores P2E7B when the signal is missing or unusable without a clear low or high reading, e.g. after a lost supply, a broken connection or a dead sensor. In TI's excitation stage a single or a pair of sensors, shunt amplifiers or isolated Hall parts, closes the field loop. No manufacturer documents P2E7B publicly. Low and high signal are P2E29 and P2E2A, implausible values P2E28. Without a trusted value the field is cut, as Audi describes for fault signals, and the motor stops pulling.

Likely causes

Supply or reference of the excitation current sensor lost
Open or corroded connection between sensor and motor controller
Excitation current sensor or its isolated amplifier failed
Measuring input inside the inverter or motor controller defective

Symptoms

  • Electric drive warning lamp and MIL
  • Noticeably reduced power or no drive from motor A
  • Vehicle may refuse to enter ready mode

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€150–3,500
Time1–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

drive motor a excitation current sensorwiring harnesshybrid control module

Related codes

P2E28P2E29P2E2AP2E2BP0A78

References: ti.com, media.renault.com, nissan-global.com, newsroom.bmwgroup.com.