Engine code
P0603: Engine computer memory fault
How much to fix P0603? Typically $150–$470.
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $120 | $320 |
| Labor: 0.3 to 0.8 hours × $110 to $150 an hour | $33 | $120 |
| Fees: shop supplies, disposal, diagnostics | $0 | $25 |
| Total, rounded | $150 | $470 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in the US, $27.13 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, battery replacement. Which repair your car needs depends on a proper diagnosis.
The engine computer keeps a memory of learned settings, such as fuel and idle adjustments, even when the car is off. That memory failed a self-check. It often appears after a battery disconnect, a jump start or a dead battery, and may clear on its own once the computer relearns.
- Safe to drive?
- Short trips only
- Most common cause
- Recent battery disconnect or dead battery
Usually drivable. Clear the code once and see whether it returns. If it does, the computer or its power supply needs a look.
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What you may notice
- Rough shifting after a reset
- Idle may feel different
- Check-engine light
Common causes, most likely first
- Recent battery disconnect or dead battery
- Weak battery or charging fault
- Poor ground or power to the computer
- Failing engine computer
Check this first
Test the battery and the charging system before suspecting the computer. A weak battery, loose terminals or a bad ground can corrupt the memory, and fixing those costs far less than a new computer.
Other repairs that sometimes fix P0603
| Repair | Typical range, US |
|---|---|
| ECU / engine control module replacement | $410 to $2,250 |
| Diagnostic scan (check engine light) | $55 to $250 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Many states require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0603 questions
Does a dead battery cause this?
It can, since the computer loses its stored settings when power drops out. A new battery or a jump start may reset it, and the code may set once as the computer reloads its memory.
Will it fix itself?
If it was a one-time dip, clearing the code often ends it. Drive normally for a few days, and if the code does not return, no further repair is needed.
Is the computer bad?
Only if the code keeps returning with a strong battery and good grounds. Then the memory chip inside the computer may be failing, and the repair may involve replacement or specialist repair.
How much does it cost to fix P0603?
The most common fix, battery replacement, has a typical range of $150 to $470 across the US. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
Typical range in 10 metro areas
Only the labor rate changes between cities. Same parts, same hours.
| Area | Typical range, estimate |
|---|---|
| Boston area, Massachusetts | $150 to $490 |
| New York City area | $150 to $480 |
| Los Angeles area, California | $150 to $490 |
| Chicago area, Illinois | $150 to $470 |
| Houston area, Texas | $150 to $470 |
| Dallas-Fort Worth area, Texas | $150 to $470 |
| Phoenix area, Arizona | $150 to $470 |
| Atlanta area, Georgia | $150 to $470 |
| Miami area, Florida | $150 to $470 |
| Seattle area, Washington | $150 to $490 |
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Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.