All codes › P0400
P0400: Exhaust Gas Recirculation "A" Flow
What it means
The EGR system flow is outside its expected range (general fault).
Severity: Medium EGR fault may cause pinging under load.
Common causes
- Carbon-clogged EGR
- Faulty EGR valve
- Vacuum supply issue
- EGR position sensor fault
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Sometimes DIY. Inspect EGR vacuum lines and clean the valve.
Repair cost
SEEDED ESTIMATE Roughly $260–$560
Most likely repair: egr valve. Diagnosis fees, taxes and other causes are not included.
| Line | Low | High | Basis |
|---|---|---|---|
| EGR valve | $164 | $164 | Typical listed retail range, source (single example listing ($163.99)) |
| Labor 1–2.5 hr | $100 | $400 | $100–$160/hr, shop survey |
⚠️ This is an editorial placeholder range for this type of repair. It is not based on real invoices or licensed pricing data yet. Real ranges will appear here once enough reader invoices for P0400 are verified.
Verified reader invoices for P0400: 0. Share your repair bill to help build real costs.
Tools that can read P0400
- ScanFixAI: Pro $29.99/mo or $249.99/yr
- OBDAI: Annual PRO bundle $299
- BlueDriver Pro Next-Gen: $119.95 list ($99.95 sale seen)
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