Chassis, generic

C0740 Electric Power Steering Voltage Supply

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

C0740 is not publicly documented by any carmaker; publicly available J2012 lists, NHTSA bulletins and maker indexes do not contain it. The title concerns the heavy supply feed of an electric steering, which draws high currents when the wheel is turned at standstill. GM bulletin PIT5405C for 2014-17 Silverado, Sierra, Tahoe, Suburban, Yukon and Escalade shows what a weak feed does: reduced assist, kickback in the wheel, even stalling and blank displays, traced to a poor body ground, a battery cable shorting on the starter shield, high-resistance battery connections, a weak battery or a loose main power and ground connector at the rack. GM logs device power faults there as C0800. NXP describes EPS control units with integrated undervoltage monitoring that limit or stop assist when supply sags.

Likely causes

Loose or corroded main power or ground connection at the rack
Discharged or failing battery, high-resistance battery cables
Battery cable shorting elsewhere or poor body ground

Symptoms

  • Assist weakens or cuts out at low speed and full lock
  • Steering wheel jerks, other displays flicker

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–500
Time0.3–2.5 h

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

Parts involved

eps control modulepower supply wiringbattery

Related codes

C0800C0735C0745

References: static.nhtsa.gov, nxp.com.