Back to 2003 Audi A8
Help
2003 AUDI A8
4.2L V8•AWD•AUTOMATIC•gas
1 active safety recall on this vehicle — view recalls
Founding sponsor spot is openYour name on every procedure for this vehicle, permanently.Sponsor — $99 →
Repairs0Labor487Torque3149Fluid10DTC939Battery1Maintenance0Recalls1
P1420moderate severityPowertrain

Secondary Air Injection Module Short to Positive

on 2003 Audi A8 4.2L V8 · AWD

What this code means

The ECU detected a short to positive voltage in the secondary air injection control module circuit. The secondary air system cannot operate correctly for cold-start emission reduction.

Symptoms

  • Check Engine Light
  • Failed emissions test
  • Abnormal engine sound on cold start

Common causes

  • Wiring short in secondary air module circuit
  • Faulty secondary air injection module
  • Damaged connector
  • Relay failure
  • Corroded wiring

Diagnostic steps

  1. Test secondary air module circuit for shorts
  2. Inspect wiring and connector
  3. Test secondary air pump relay
  4. Check for voltage at module connector
  5. Test secondary air pump operation

Repair notes

Repair the wiring short or replace the secondary air injection control module.

🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.

Other Powertrain codes on this vehicle

🔌 Need this data in your app? It's all in the free API →
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
Stuck on this repair? Take it to The Diag Desk — ask a master tech about this exact car → real human answer within 24h, never AI
Share:XRedditFBWhatsAppThreadsEmail
⚠ STILL BEHIND THE PAYWALL
The 2003 Audi A8 repair data is incomplete because no one has sponsored it yet. For $99, we generate the full step-by-step procedures, then fact-check them with a second AI pass and your expert review. Your name on every procedure, permanently.
The same data would cost $169/mo from Mitchell1 or $30/year from ALLDATAdiy — and you'd be renting access, not freeing it. Sponsor once, free forever.
Sponsor the Audi A8 — $99 →
Building an app?
Free API access to all this data — 10 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →