What Does P02B2 Mean?
The ECM has detected that the individual fuel trim correction for cylinder 7 has reached its maximum enrichment limit. The system is adding the maximum possible fuel to cylinder 7 but still detects a lean condition, indicating a substantial fuel delivery deficit or unmetered air leak affecting that cylinder. The driver may notice misfire symptoms, rough idle, hesitation, and reduced power from the engine.
Common Causes
30%
Clogged or partially restricted cylinder 7 fuel injector reducing fuel delivery below the ECM's compensation capability
25%
Vacuum leak at the cylinder 7 intake runner gasket or port allowing unmetered air into that cylinder
20%
Faulty cylinder 7 injector electrical circuit causing reduced pulse width or intermittent injector operation
15%
Low fuel pressure at the rail causing inadequate fuel delivery to cylinder 7 under demand
10%
Exhaust leak near the cylinder 7 port introducing false lean readings to the O2 sensor
Diagnostic Steps
1
Review live data for cylinder 7 individual fuel trim — confirm it is at or near the maximum positive correction limit (typically +25% to +30%) indicating the ECM cannot supply enough fuel.
2
Perform a smoke test on the intake manifold focusing on the cylinder 7 intake runner, gasket surfaces, and associated vacuum connections to identify air leaks.
3
Compare injector flow rates using an injector balance test by disabling each injector individually and monitoring rpm drop — cylinder 7 should produce a similar drop as the others.
4
Check fuel rail pressure under key-on engine-off and at idle (typically 55-62 PSI for port injection), then verify it holds under load with a snap throttle test.
5
Inspect the cylinder 7 injector connector for corrosion, backed-out pins, or wiring damage, and measure injector resistance (typically 11-17 ohms).
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The ECM has detected that the individual fuel trim correction for cylinder 7 has reached its maximum enrichment limit. The system is adding the maximum possible fuel to cylinder 7 but still detects a lean condition, indicating a substantial fuel delivery deficit or unmetered air leak affecting that ...
The most common cause of P02B2 (Cylinder 7 - Fuel Trim at Max Limit) is: Clogged or partially restricted cylinder 7 fuel injector reducing fuel delivery below the ECM's compensation capability
Typical repair costs for P02B2 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Driving is possible but not recommended for extended distances. A maxed-out lean fuel trim on cylinder 7 causes elevated combustion temperatures that risk catalytic converter damage from misfires, and in extreme cases, piston or valve damage from lean detonation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02B2 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
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