C0740 code meaning
Electric Power Steering Voltage Supply
What C0740 means
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.
C0740 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C0740
- Assist weakens or cuts out at low speed and full lock
- Steering wheel jerks, other displays flicker
Common causes of C0740
- Most likelyLoose or corroded main power or ground connection at the rack
- PossibleDischarged or failing battery, high-resistance battery cables
- Less likelyBattery cable shorting elsewhere or poor body ground
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Eps control modulePower supply wiringBattery
What each part of C0740 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 40 | The exact fault in that area. |
What to do next
- Note C0740 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0740
What does C0740 mean?
C0740 means "Electric Power Steering Voltage Supply". C0740 is not publicly documented by any carmaker; publicly available J2012 lists, NHTSA bulletins and maker indexes do not contain it. It is a generic code, so it means the same on every make.
Is it safe to drive with C0740?
Drive gently and only to a workshop. With C0740 the car can go into limp mode (reduced power) to protect itself.
Will C0740 fail an emissions test?
C0740 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0740 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0740 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.