Powertrain, generic · Hybrid propulsion

P0A46 Drive Motor B Position Sensor Circuit Range/Performance

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

P0A46 reports that the motor B resolver still delivers a signal, but one that is degraded or not plausible. GM uses the same check as P0A40 for its second motor: sine or cosine above 4.0 V, with a failure counted when it persists for 0.2 to 0.4 s of a 2 s window (Type A, one trip in the 2011 and 2016 tables). Mitsubishi (2023 Outlander PHEV rear motor) sets P0A46 when its internal resolver status words A, B or C stay failed for 0.18 s, and replaces the rear motor assembly. A GM-related patent explains the idea: a degraded signal shows as a large mismatch between sine and cosine amplitudes. P0A45 is a full signal loss. Expect a hybrid warning and loss of motor B drive.

Likely causes

Resolver of motor B delivering unequal or distorted sine/cosine signals

High contact resistance or moisture in the resolver connector

Fault inside the rear motor assembly incl. bearing damage (Mitsubishi)

Damaged shielding letting inverter noise into the resolver lines

Symptoms

Hybrid system warning and MIL
Rear or second motor disabled, reduced traction or power
Jerky torque delivery before the fault sets

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€200–6,000

Time2–10 h

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

Parts involved

drive motor b position sensorwiring harnesshybrid control module

References: gsi.ext.gm.com, gsi.ext.gm.com, mitsubishitechinfo.com, patents.google.com.