What Does P02D2 Mean?
The ECM has detected that Cylinder 4 fuel injector offset learning correction has reached its minimum allowable limit. The adaptive fuel control is subtracting the maximum fuel from Cylinder 4 but the correction needed exceeds the allowable range. Cylinder 4 is over-fueling relative to the other cylinders, typically caused by a leaking or over-flowing injector.
Common Causes
40%
Leaking or stuck-open Cylinder 4 fuel injector causing excess fuel delivery that exceeds adaptive learning limits
25%
Mismatched or incorrect replacement injector in Cylinder 4 with a higher flow rate than specified
20%
Fuel pressure regulator malfunction causing elevated system pressure and disproportionate Cylinder 4 over-delivery
15%
Carbon or varnish buildup on Cylinder 4 injector tip altering spray pattern and increasing effective flow
Diagnostic Steps
1
Step 1: Retrieve and compare injector offset learning values across all cylinders. Confirm Cylinder 4 has the most negative correction, indicating the ECM is maximally reducing its fuel delivery.
2
Step 2: Run a cylinder power balance test monitoring individual cylinder contribution. Check short-term fuel trims at idle and 2500 RPM.
3
Step 3: Swap Cylinder 4 injector with a known-good cylinder, clear adaptations, and drive through a relearn cycle. If the over-fueling follows the injector, replace it.
4
Step 4: Measure fuel rail pressure with a mechanical gauge at idle, at 2500 RPM, and under load. Check for elevated pressure from a sticking fuel pressure regulator.
5
Step 5: If injector tests normal, perform a compression and leak-down test on Cylinder 4 to rule out mechanical issues such as a leaking intake valve that could affect combustion efficiency and offset learning.
Estimated Repair Cost
$150 - $600
Parts + labor, varies by vehicle and location
The ECM has detected that Cylinder 4 fuel injector offset learning correction has reached its minimum allowable limit. The adaptive fuel control is subtracting the maximum fuel from Cylinder 4 but the correction needed exceeds the allowable range. Cylinder 4 is over-fueling relative to the other cyl...
The most common cause of P02D2 (Cylinder 4 Fuel Injector Offset Learning At Min Limit) is: Leaking or stuck-open Cylinder 4 fuel injector causing excess fuel delivery that exceeds adaptive learning limits
Typical repair costs for P02D2 range from $150 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Persistent over-fueling on Cylinder 4 can cause catalytic converter overheating from unburned hydrocarbons, increased emissions, and accelerated wear from cylinder wall fuel washing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P02D2 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection System
Difficulty
Type
Generic (SAE)
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