P0638 on Volvo
Throttle Actuator Control Range/Performance Bank 1
P0638 on Volvo vehicles indicates throttle actuator control range/performance bank 1. Au7o has documented this code across 1 Volvo model — most commonly on XC70. 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. Typical repair costs on Volvo range from $200 to $600, depending on the specific model and root cause.
Common Causes of P0638
- •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
P0638 on Volvo by Model
Volvo XC70(1 issue)
- Electronic Throttle Module (ETM) Failure2001-2004
The ETM fails due to internal solder joint cracking, 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 warranty coverage in some markets.
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View P0638 across all makes →Frequently Asked Questions
What does P0638 mean on 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 specifically, this code is documented across 1 model.
What causes P0638 on Volvo vehicles?▼
Common causes on Volvo: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0638 on a Volvo?▼
Repair costs on Volvo range from $200 to $600, depending on the specific model and root cause.
Which Volvo models have P0638 documented?▼
Au7o has documented P0638 on 1 Volvo model: XC70.