What causes fault code P02B9?

• Most likely: Restricted or partially clogged fuel injector on cylinder 6 • Likely: Intake manifold vacuum leak or injector O-ring leak specific to cylinder 6 • Possible: Faulty ignition coil or spark plug leading to poor combustion efficiency • Rare: Mechanical engine problem (low compression) or wiring harness resistance to the injector

How do you fix fault code P02B9?

STEP 1: Visually inspect the intake manifold and vacuum lines near cylinder 6 for leaks. Check the injector connector for corrosion or loose pins. STEP 2: Perform an injector balance test using a scan tool. Measure injector resistance; it should typically be 12-16 Ohms. Verify 12V supply and ECU ground switching. STEP 3: Use an oscilloscope to monitor the injector waveform (look for the inductive kick/voltage peak). Perform a compression or leak-down test on cylinder 6 to rule out mechanical issues. STEP 4: Replace the fuel injector on cylinder 6 if localized leaning is confirmed. Perform fuel trim reset/adaptation using an OEM-capable scan tool.

Powertrain (Engine & Gearbox)Standard EOBD

P02B9 - Cylinder 6 - Injector Restricted

Q: What are the symptoms of fault code P02B9?

• Check Engine Light (MIL) illuminated • Rough idling or engine shuddering • Reduced engine power during acceleration • Increased fuel consumption • Smell of unburned fuel from the exhaust

Last updated:1 February 2026

Related:Drivstoffinjektor sylinder 6, Engine Control Unit (ECU/PCM), Ignition Coil, Innsugsmanifoldpakning, Oxygen Sensor (O2)

System

Powertrain (Engine & Gearbox)

Related Fault Codes

P0200

Injector Circuit Malfunction

P0201

Cylinder 1 Injector Circuit Open

P0202

Injector Circuit - Cylinder 2 - Malfunction

P0203

Injector Circuit - Cylinder 3

Technical Description

P02B9 is set when the Engine Control Unit (ECU) detects that cylinder 6 is running lean and has reached its maximum enrichment limit. The ECU monitors the crankshaft speed variations (misfire monitor) and O2 sensor feedback to determine individual cylinder contribution. If cylinder 6 requires significantly more fuel than the others to maintain stoichiometric balance, this code is triggered. It typically points to a restricted fuel injector or unmetered air entering that specific cylinder.

Possible Causes

Restricted or partially clogged fuel injector on cylinder 6

Intake manifold vacuum leak or injector O-ring leak specific to cylinder 6

Faulty ignition coil or spark plug leading to poor combustion efficiency

Mechanical engine problem (low compression) or wiring harness resistance to the injector

Symptoms

Check Engine Light (MIL) illuminated

Rough idling or engine shuddering

Reduced engine power during acceleration

Increased fuel consumption

Smell of unburned fuel from the exhaust

Do you also have
other fault codes?

See how P02B9 connects with your other fault codes. Our advanced analysis tool identifies causal relationships and root causes directly.

Analyze multiple codes

P02B9 - Cylinder 6 - Injector Restricted

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have
other fault codes?

P02B9 - Cylinder 6 - Injector Restricted

Related Fault Codes

Technical Description

Possible Causes

Symptoms

Recommended Solution

Workflow

Mechanic's Tip

Do you also have other fault codes?

Do you also have
other fault codes?