P0638

Throttle Actuator Control Range/Performance Bank 1

Throttle actuator control Generic OBD-II High

What it means

P0638 means the throttle actuator control for bank 1 isn't achieving the throttle position the ECM commanded. Because this is the electronic throttle, the car often drops into reduced-power 'limp' mode and may hesitate or stall. It's commonly the throttle body itself or its wiring, and should be addressed promptly.

High

Can I keep driving? Limited — the car often drops into reduced-power 'limp' mode and may hesitate or stall, so drive cautiously and address it promptly.

Real-world scan data

Seen in

1,115

scans in the past year

Found in

0.2%

of scans

0.3%

of scans that found faults

Appears alongside · share of P0638 scans

P0201in 25.4% of scans

P0202in 24.3% of scans

P0203in 23.8% 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

Reduced engine power or acceleration (limp mode)
Check-engine light on
Poor or sluggish throttle response
Hesitation or stalling during acceleration

Common causes

Most likely first

Faulty throttle body / throttle actuator motorLikely
Dirty or sticking throttle plateCommon
Damaged wiring or connectors in the throttle actuator circuitCommon
Loose or corroded electrical connectionsLess often
Faulty engine control module (ECM)Less often

How to diagnose & fix

Work through it in order

Inspect the throttle body connector and wiring for damage, corrosion, or loose pins.
Clean the throttle body if the plate is carbon-fouled or sticking.
Test the throttle actuator motor and position feedback; replace the throttle body if it can't reach commanded position.
Perform a throttle relearn after any repair; if the fault stays, suspect the ECM. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0638?+

Only cautiously. The electronic throttle may limit power or cause hesitation or stalling, which is risky in traffic. Get it fixed promptly.

Can I just clear P0638?+

It usually comes right back and drops into limp mode again until the throttle body or wiring is repaired. A throttle relearn is often needed after the fix.

Read & clear P0638 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