C05D6 code meaning
Power Steering Control Module Processor Performance
What C05D6 means
The electric power steering controller has found that its own processor, or the cross-check between its processors, is not working as expected. Toyota documents the code as C05D604 in the ECU of the EPS steering gear: 2019–2020 RAV4 and RAV4 Hybrid light the EPS warning in red or yellow at start-up or while driving (T-SB-0061-20), and the 2022 Tundra and Lexus LX 600 log it at start-up, often together with C15D704. In each case the fix is reprogramming the gear ECU with revised logic. Many EPS units pair a main and a monitoring microcontroller that must both enable the motor relay; Mando describes such a start-up check. If the self-test fails, assist is reduced or switched off, so steering becomes heavy.
C05D6 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of C05D6
- Red or yellow power steering warning lamp
- Steering suddenly heavier or assist reduced
- Fault appears mainly right after starting the vehicle
Common causes of C05D6
- Most likelyEPS controller software flags a false processor fault, update available
- PossibleSupply voltage dip during engine start disturbs the self-test
- PossibleInternal hardware fault in the steering control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Eps module
What each part of C05D6 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| D6 | The exact fault in that area. |
What to do next
- Note C05D6 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 C05D6
What does C05D6 mean?
C05D6 means "Power Steering Control Module Processor Performance". The electric power steering controller has found that its own processor, or the cross-check between its processors, is not working as expected. It is a generic code, so it means the same on every make.
Is it safe to drive with C05D6?
Drive gently and only to a workshop. With C05D6 the car can go into limp mode (reduced power) to protect itself.
Will C05D6 fail an emissions test?
C05D6 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 C05D6 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will C05D6 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.