P2B88
Intake Air O2 Sensor Circuit Bank 1
The ECM detects a generic fault on the intake air oxygen sensor signal circuit on bank 1. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Common causes
Ordered by how often each turns out to be the cause.
- Intake air O2 sensor failedCommon
- Wiring or connector faultPossible
Parts involved
- Intake Air O2 Sensor B1
- Intake Air O2 Sensor Heater B1
- Wiring Harness
- ECM
P2B88 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.