Powertrain, generic (extended)

P28EA Shift Motor Position Sensor Circuit Range/Performance

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

P28EA covers a position signal that is electrically valid but implausible: the two channels disagree, the value does not move although the motor runs, or the actuator ends up away from the expected detent. Hyundai uses the code in bulletin 22-AT-001H for its shift-by-wire models with two failure types, P28EA71, SBW actuator stuck, and P28EA77, commanded position not reached. The diagnosis compares target and actual lever positions in the SCU data and checks that both position sensor readings total about 100 percent; a related bulletin covers replacing the position sensor or actuator. A Denso patent explains why the check works: the controller relates the encoder count to changes of two output shaft signals. CARB requires rationality checks on inputs. Shifting is limited or refused.

Likely causes

SBW actuator stuck or not reaching the commanded position
Position sensor channels drifting apart (sum no longer near 100 percent)
Intermittent contact in the sensor or actuator harness

Symptoms

  • Shifter system malfunction message in the cluster
  • Cannot shift out of Park or into the requested range
  • Gear display does not match the selected range

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time1–4 h

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

Parts involved

shift motorshift motor position sensortcm

Related codes

P28E7P28E8P28E9P28E5P28EC

References: static.nhtsa.gov, patents.google.com, law.cornell.edu.