P0602

Control Module Programming Error

Q: Is it safe to drive with P0602?

Often not — the engine may run poorly or not start at all. Have the module correctly reprogrammed before depending on the car.

Q: Can I just clear P0602?

Clearing won't fix a programming error. The ECM needs to be properly reflashed with the correct calibration, usually with a capable scan tool or at a shop.

ECM / computer Generic OBD-II High

What it means

P0602 means the ECM has detected an error in its own programming, often after an interrupted or incorrect software flash. Because the module runs the engine, this can cause poor running or prevent the engine from starting until it's correctly reprogrammed. It usually needs proper reflashing with the right calibration.

High

Can I keep driving? Often not — a programming error can leave the engine running poorly or unable to start, so plan to have it correctly reprogrammed before relying on the vehicle.

Real-world scan data

Seen in

251

scans in the past year

Found in

<0.1%

of scans

0.1%

of scans that found faults

Appears alongside · share of P0602 scans

P0604in 38.2% of scans

P0606in 37.5% of scans

P0562in 27.1% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Engine may not start or is hard to start
Stalling, rough idle, or poor performance
Other odd module or drivability faults after recent service

Common causes

Most likely first

Incomplete or corrupted ECM software flash (often an interrupted reprogramming)Likely
Incorrect or mismatched calibration loaded into the ECMCommon
Failed ECM hardware or memoryCommon
Electrical problems (weak battery, poor power/ground) during programmingLess often

How to diagnose & fix

Work through it in order

Confirm battery voltage and ECM power/ground are solid; low voltage during a flash is a common trigger.
Reprogram (reflash) the ECM with the correct, up-to-date calibration for the vehicle.
Verify the reprogramming completed successfully and follow the exact procedure, ignition, and voltage requirements.
If the module fails to accept programming, replace the ECM and program it. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0602?+

Often not — the engine may run poorly or not start at all. Have the module correctly reprogrammed before depending on the car.

Can I just clear P0602?+

Clearing won't fix a programming error. The ECM needs to be properly reflashed with the correct calibration, usually with a capable scan tool or at a shop.

Read & clear P0602 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX