What Does P0288 Mean?
This code signals a cylinder 9 contribution or balance fault where cylinder 9 is underperforming relative to the other cylinders. Found on V10, V12, and similar large engines, the ECM detects this through crankshaft speed variation analysis during each cylinder's power stroke. The driver will experience reduced power, rough running, vibration, and potentially increased exhaust emissions.
Common Causes
35%
Cylinder 9 fuel injector failing — restricted flow, worn nozzle tip, or poor atomization
25%
Mechanical compression loss on cylinder 9 — ring wear, valve erosion, or gasket leak
20%
Electrical fault in cylinder 9 injector circuit
12%
Intake manifold restriction or charge air imbalance at cylinder 9
8%
Exhaust restriction or backpressure issue at cylinder 9
Diagnostic Steps
1
Confirm the imbalance by comparing all cylinder contribution rates in live data — verify the deviation is consistent across different operating conditions (idle, part-load, full-load).
2
Perform a relative compression test via cranking RPM analysis — this provides a quick, non-invasive screen for mechanical issues on all cylinders simultaneously.
3
Swap the cylinder 9 injector with a known-good cylinder, clear codes and fuel trim adaptations, then operate the engine to track whether the fault follows the injector.
4
If the fault remains at cylinder 9 after injector swap, perform a leak-down test at TDC — listen for air escaping at the intake, exhaust, crankcase, and cooling system.
5
On V10/V12 engines, verify that the fuel rail pressure is adequate at the cylinder 9 injector location — pressure drop along long fuel rails can starve end-of-rail injectors.
Estimated Repair Cost
$200 - $1,800
Parts + labor, varies by vehicle and location
This code signals a cylinder 9 contribution or balance fault where cylinder 9 is underperforming relative to the other cylinders. Found on V10, V12, and similar large engines, the ECM detects this through crankshaft speed variation analysis during each cylinder's power stroke. The driver will experi...
The most common cause of P0288 (Cylinder 9 Contribution/Balance Fault) is: Cylinder 9 fuel injector failing — restricted flow, worn nozzle tip, or poor atomization
Typical repair costs for P0288 range from $200 to $1,800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Driveable at reduced power levels. On large engines, a single weak cylinder is partially masked by the remaining cylinders but still causes elevated exhaust temperatures. Schedule professional diagnosis to prevent secondary damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0288 to identify the root cause.
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Quick Info
Category
Powertrain
System
Fuel Injection / Engine Mechanical
Difficulty
Type
Generic (SAE)
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