P222F Barometric Pressure Sensor A/B Correlation

P222F is meant for engines with two barometric sensors whose readings should agree but drift apart, without the software being able to say which of the two is wrong. No maker documents this code publicly. GM, the one maker that publishes tables for a sensor B, resolves the comparison differently: it pulls in manifold and boost pressure as further references, singles out the deviating sensor and stores P222B for sensor B or P2227 for sensor A. Ford likewise uses a three-sensor vote for P2227. A pure A/B comparison has no tiebreaker, which explains why the code is rarely seen. CARB requires rationality checks of input sensors. Both sensors, their supply and any leaks in the lines feeding them should be checked.

Likely causes

Symptoms

• Check engine light
• The two barometric readings differ clearly on the scan tool

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, gsi.ext.gm.com, newtonnet.co.uk.