What Does P02DB Mean?
The ECM has detected that Cylinder 8 fuel injector offset learning correction has reached its maximum allowable limit. The PCM is adding maximum fuel to Cylinder 8 but cannot compensate for the under-fueling condition. Cylinder 8 is delivering significantly less fuel than commanded, typically caused by a restricted injector or localized lean condition on V8 and larger engine configurations.
Common Causes
40%
Partially clogged or internally restricted Cylinder 8 fuel injector with reduced flow from deposits or contamination
25%
Failing Cylinder 8 injector solenoid with elevated coil resistance causing incomplete valve opening and reduced flow
20%
Low fuel system pressure on the bank feeding Cylinder 8 from a weak fuel pump or restricted fuel supply components
15%
Vacuum leak at Cylinder 8 intake port or manifold gasket causing unmetered air ingestion and localized lean running
Diagnostic Steps
1
Step 1: Retrieve injector offset learning values for all eight cylinders. A strongly positive offset on Cylinder 8 confirms under-fueling relative to the other cylinders.
2
Step 2: Perform an injector flow bench test to compare Cylinder 8 output against the injector set. Flow should be within 5% of the group average.
3
Step 3: Swap Cylinder 8 injector with another cylinder on the same bank, clear adaptations, and complete a relearn drive cycle. If the lean fault follows the swapped injector, replace or clean it.
4
Step 4: Smoke test the intake manifold area around Cylinder 8, paying special attention to rear cylinder runner seals and gasket surfaces that are difficult to visually inspect.
5
Step 5: Measure fuel pump pressure and volume output at the fuel rail under idle and wide-open throttle conditions. Verify adequate fuel delivery to all eight cylinders.
Estimated Repair Cost
$150 - $700
Parts + labor, varies by vehicle and location
The ECM has detected that Cylinder 8 fuel injector offset learning correction has reached its maximum allowable limit. The PCM is adding maximum fuel to Cylinder 8 but cannot compensate for the under-fueling condition. Cylinder 8 is delivering significantly less fuel than commanded, typically caused...
The most common cause of P02DB (Cylinder 8 Fuel Injector Offset Learning At Max Limit) is: Partially clogged or internally restricted Cylinder 8 fuel injector with reduced flow from deposits or contamination
Typical repair costs for P02DB range from $150 to $700, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Under-fueling Cylinder 8 causes lean misfires, elevated exhaust gas temperatures, and potential catalytic converter overheating. Engine roughness and power loss are common symptoms.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02DB to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
Recommended Tools
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