P1391 on Toyota Prius
Glow Plug Circuit Low Input (Bank #1)
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to Toyota Prius context without treating complaints as confirmed diagnoses.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
- SAE J2012 Diagnostic Trouble Code Definitions — Generic diagnostic trouble code definition reference for P1391.
- NHTSA recalls, complaints, and manufacturer communications — Used to check public owner complaint context, recall status, and safety-related manufacturer communications by VIN or vehicle.
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What P1391 Means on Your Toyota Prius
P1391 is a diagnostic trouble code indicating: Glow Plug Circuit Low Input (Bank #1). This code relates to the manufacturer-specific powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real Toyota Prius Owner Reports
Source: NHTSA Complaints Database
"I brought my toyota prius to toyota dealer as abs alert was on and i lost controlling the brake. toyota dealer gave me an estimate for repair at $2,850."
"During a hard braking, felt brake pedal softer and less responsive braking. Now ABS Icon, Brake Icon, and Traction Icon is on. Confirmed Code P1391 in ABS system."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on Toyota Prius
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
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3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.