What Does P02B6 Mean?
The ECM has detected that the individual fuel trim correction for cylinder 8 has reached its maximum enrichment limit. The system is adding the maximum allowable extra fuel to cylinder 8 but still cannot achieve a stoichiometric mixture, indicating a severe lean condition on that cylinder. The driver may notice a cylinder 8 misfire, rough idle, hesitation under acceleration, and reduced power.
Common Causes
30%
Clogged or partially restricted cylinder 8 fuel injector unable to deliver adequate fuel
25%
Vacuum leak at the cylinder 8 intake runner gasket or port allowing unmetered air entry
20%
Faulty cylinder 8 injector electrical circuit reducing pulse width or causing intermittent operation
15%
Low fuel pressure at the rail causing inadequate fuel delivery to cylinder 8
10%
Exhaust leak near the cylinder 8 port introducing false lean readings to the O2 sensor
Diagnostic Steps
1
Review live data for cylinder 8 individual fuel trim — confirm it is at or near the maximum positive correction limit (typically +25% to +30%).
2
Perform a smoke test on the intake manifold focusing on the cylinder 8 intake runner, gasket surfaces, and vacuum connections.
3
Run an injector balance test by disabling each injector individually and comparing rpm drops — cylinder 8 should produce a similar drop as the others.
4
Check fuel rail pressure at key-on engine-off and at idle (typically 55-62 PSI), then verify it maintains pressure under load.
5
Inspect the cylinder 8 injector connector for corrosion, backed-out pins, or wiring damage, and measure injector resistance (typically 11-17 ohms).
6
If the vehicle has a V8 configuration, also check the fuel rail crossover tube or balance line for restrictions that could starve the rear bank.
Estimated Repair Cost
$150 - $500
Parts + labor, varies by vehicle and location
The ECM has detected that the individual fuel trim correction for cylinder 8 has reached its maximum enrichment limit. The system is adding the maximum allowable extra fuel to cylinder 8 but still cannot achieve a stoichiometric mixture, indicating a severe lean condition on that cylinder. The drive...
The most common cause of P02B6 (Cylinder 8 - Fuel Trim at Max Limit) is: Clogged or partially restricted cylinder 8 fuel injector unable to deliver adequate fuel
Typical repair costs for P02B6 range from $150 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Driveable short distances but extended driving is not recommended. A maxed-out lean fuel trim on cylinder 8 causes elevated combustion temperatures risking catalytic converter damage and potential piston or valve damage from detonation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02B6 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel System
Difficulty
Type
Generic (SAE)
Recommended Tools
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