P1533
AAI Circuit Malfunction
Findings, check these first
- Failed air assist injector
- Open or shorted AAI circuit
- Clogged air assist passages
- Blown AAI fuse
- Corroded connector
Standard procedure
- Check the AAI fuse
- Test injector resistance
- Inspect air passages for clogging
- Verify command signal
- Replace the injector after circuit checks
Code lookup
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Sources and review
Review: qualified. Read the source limits below.
- OBDII.pro: P1533 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1533: AAI Circuit Malfunction
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Last updated 2026-09-06.
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