U0521Network · Invalid data & softwareGeneric (SAE) code

U0521: Invalid Data Received from Power Steering Control Module

Other modules receive implausible EPS torque or angle data. EPS reduces or disables assist; the EPS warning lamp comes on.

Typical labor cost
$65–$500 est.
30 min–4 h at an assumed $125/hr · parts extra · use your rate
Most common fix
Torque sensor drift
DIY difficulty: Hard · usually a shop job
01 —What it means

What U0521 means

U0521 is a generic OBD-II network code in the invalid data & software group. In plain English: a module received data that didn’t make sense from the Power Steering Control Module.

U
Network
0
Generic (SAE)
5
Subsystem group
21
Specific fault
How to read U0521. We group it under Invalid data & software.
Check engine light
Usually on
Emissions-related
No
Limp mode possible
Yes
Drive cycle to clear
Not required
Code data: OBDex (CC0)

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02 —Symptoms

Symptoms

What drivers typically notice
  • Multiple warning lights may illuminate
  • Affected modules may go into limp mode or shut down
  • Specific functions inoperative depending on module
  • Diagnostic tools may show communication faults
Code data: OBDex (CC0)
03 —Causes

Common causes

Ranked from most to least likely
  1. 01Torque sensor driftPossible
  2. 02Gateway module routing CAN messages incorrectlyLess likely
  3. 03CAN terminating resistor (120 Ω) drifted out of specLess likely
Code data: OBDex (CC0)
04 —Severity

Can I drive with U0521?

Urgent

Drive carefully and get it checked soon.

Steering assist may drop out, making the wheel heavy at low speed. Avoid driving if steering becomes very heavy or erratic.

Why we rate it urgent

  • Steering assist may be reduced or lost
  • Can put the vehicle in limp mode (reduced power)
  • Turns on the check engine light

Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.

Code data: OBDex (CC0)
05 —Diagnosis

How to diagnose U0521

General procedure — follow the service manual for your vehicle
  1. 1

    Confirm the code and save freeze-frame data

    Read the codes with an OBD-II scan tool and note every code, not just U0521. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.

  2. 2

    Check for related codes first

    Look for U0420. Related codes often share a cause; a circuit or sensor code usually needs fixing before a performance code like this one.

  3. 3

    Check module power, ground and the data bus

    Confirm the module named in the code has battery voltage, ignition feed and a good ground. With the battery disconnected, a healthy CAN bus usually measures about 60 ohms between CAN-High and CAN-Low at the OBD port. Inspect connectors for corrosion and pushed-out pins.

  4. 4

    Test the likely causes in order

    Start with the most likely cause and work down: Torque sensor drift; gateway module routing CAN messages incorrectly; CAN terminating resistor (120 Ω) drifted out of spec. Test before replacing parts.

  5. 5

    Check for recalls and service bulletins

    Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.

  6. 6

    Clear the code and verify the repair

    After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.

Code data: OBDex (CC0)
06 —Cost

U0521 repair cost estimate

Labor only — set your local shop rate
Labor estimate for U0521
$65–$500
30 min–4 h of labor × $125/hr (assumed rate) · parts extra

Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.

DIY difficulty
Hard
Good DIY job?
Usually a shop job

Involved testing or major parts. Most owners use a shop.

Code data: OBDex (CC0)
07 —Components

Parts and systems involved

  • EPS module
Code data: OBDex (CC0)
09 —FAQ

U0521 FAQ

What does U0521 mean?

U0521 means “Invalid Data Received from Power Steering Control Module”. Other modules receive implausible EPS torque or angle data. EPS reduces or disables assist; the EPS warning lamp comes on.

Is U0521 serious? Can I keep driving?

We rate U0521 as urgent severity. Drive carefully and get it checked soon. Steering assist may drop out, making the wheel heavy at low speed. Avoid driving if steering becomes very heavy or erratic.

What causes U0521?

The most common causes, from most to least likely: Torque sensor drift; Gateway module routing CAN messages incorrectly; CAN terminating resistor (120 Ω) drifted out of spec. Test before replacing parts, because several causes can set the same code.

How much does it cost to fix U0521?

Typical labor is about $65–$500 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.

Can I fix U0521 myself?

DIY difficulty is hard. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.

Will U0521 clear itself?

If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.

Code data: OBDex (CC0)