P0638 on Volvo: How to Diagnose & Fix
Throttle Actuator Control Range/Performance Bank 1
1 Volvo model · 1 documented issue · 1 critical · $200-$600 repair
P0638 on Volvo by model: symptoms, diagnosis and fix
The ETM fails when throttle position sensor irregularities, a dirty throttle housing and/or inefficient software calibration trigger a fault, causing reduced power, limp mode, and check engine light. This is the same issue that affects all Volvo P2 platform vehicles (S60, V70, XC70). Volvo extended ETM warranty coverage in the U.S. and Canada to 10 years/200,000 miles on 1999-2002 cars, and the 2001 XC70 was also recalled for a software upgrade (NHTSA 06V441000).
Common Symptoms
- Reduced engine power
- Limp mode
- Check engine light
- Rough idle
- Stalling
How to Fix
Have a Volvo dealer confirm the 06V441000 software upgrade was installed, then clean or replace the ETM as needed. Clear adaptation values after installation. Some shops offer ETM rebuilds at lower cost than new units.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- XeMODeX VO.1020.36001822.00.24-PP pre-programmed contactless ETM
replace a tested failed early ETM with a pre-programmed contactless dual-sensor remanufactured unit Fitment/availability: 2001 Volvo XC70 Turbo using a listed 36001821/36001822/8603652/8644344-family Magneti Marelli ETM; excludes 2002-20…
- XeMODeX VO.1020.30711554H.00.20 contactless electronic throttle body
replace the diagnosed later electronic throttle body after year, engine, original number and wiring checks Fitment/availability: 2002-2004 Volvo XC70 Turbo within the supplier's 2002-2007 application using listed 30711554/30711544/306500…
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Sources for this issue (3)
P0638 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0638 mean on a Volvo?
P0638 stands for "Throttle Actuator Control Range/Performance Bank 1." This code means the engine computer detected that the electronic throttle plate (Bank 1) is not opening or closing to the position it commanded. The PCM monitors throttle actuator position against the desired angle and sets this code when they disagree. This can trigger reduced-power 'limp' mode, hesitation, or unexpected changes in engine response, which makes it a safety-relevant fault. On Volvo it is documented across 1 model: XC70.
What are the most common causes of P0638?
The most common causes of P0638 are: Dirty or carbon-clogged throttle body, Faulty throttle actuator motor, Failed throttle position sensor, Corroded or loose throttle body connector, Wiring faults in the throttle control circuit, Mechanical binding of the throttle plate, PCM fault. The specific cause varies by vehicle.
How much does it cost to fix P0638 on a Volvo?
Published repair estimates on Volvo range from $200 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.