Hydraulic Pressure Unit Loss of Pressure
The P0944 code means the vehicle's onboard diagnostic system has detected: Hydraulic Pressure Unit Loss of Pressure. This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $1,200 (parts and labor)
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What Are the Symptoms of P0944?
- Check Engine Light on
- A scan tool shows Hydraulic Pressure Unit Loss of Pressure as the stored fault
- Drivability may be normal - many faults in this circuit show no symptom the driver notices
- The system may fall back to a default strategy until the fault is cleared
What Causes P0944? (Most Likely First)
- Wiring or connector fault at the hydraulic pressure unit - chafed harness, corroded pins, or a loose ground High
- Failed hydraulic pressure unit Medium
- A supply or reference voltage problem shared with other circuits, which usually sets companion codes too Medium
- Control module fault - rare, and only after the wiring and the component have both been ruled out Low
Can I Still Drive with P0944?
Short distances only. P0944 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What does P0944 mean?
Hydraulic Pressure Unit Loss of Pressure. That definition comes from SAE J2012, the standard that assigns generic OBD-II trouble code meanings.
Is P0944 the same on every vehicle?
The definition is standardized, but the exact test that sets it, the specified voltages and the physical location of the component vary by make and model. Check your vehicle's service information for those.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P0944?
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Read ALL stored codes first. Faults in this area often set several codes at once, and the cheapest cause is usually shared wiring rather than the part.
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Inspect the connector and harness at the hydraulic pressure unit for corrosion, backed-out pins, and chafing before testing anything electrically.
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Back-probe the circuit with the connector attached and compare the reading against the manufacturer's specification for your vehicle - generic values do not apply across makes.
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Check power, ground and reference voltage feeding the circuit before condemning the component.
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Replace the component only after the wiring tests good. Confirm the repair by clearing the code and verifying it does not return under the conditions that set it.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Which Vehicles Commonly Get P0944?
- 2010-2020 Ford F-150
- 2012-2019 Chevrolet Silverado
- 2011-2020 Toyota Camry
- 2009-2019 Honda Accord
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