VW CBAB 2.0 TDI CR Injector Problems: Symptoms & Repair (UK)

The CBAB marked VW Group's transition from pump-duse to common-rail injection. Found in the Golf Mk6, Audi A3 8P, and Skoda Octavia, it uses Bosch solenoid injectors at 1,800 bar. This was the first generation of VW common-rail 2.0 TDI.

Common CBAB injector failure symptoms

• Rough idle and vibration: Common-rail injector wear causes uneven fuel delivery, producing cabin vibration.
• DPF regeneration issues: Worn injectors cause incomplete combustion, accelerating DPF soot loading.
• Engine management light: Injector deviation codes stored when correction values exceed limits.
• Cold start difficulty: Worn nozzles fail to atomise fuel correctly during pilot injection.

Why CBAB injectors fail

• fuel contamination
• high-pressure wear cycles
• carbon buildup
• poor fuel quality
• internal valve wear

How to diagnose CBAB injector faults

1. Read fault codes: Connect an OBD-II scanner and note any injector-related codes (P0201–P0204, P2146, P2149). This identifies which cylinder is affected.
2. Perform a leak-off test: Disconnect the fuel return pipes and route into measuring containers. Run the engine at idle for 60 seconds. Compare volumes per cylinder against manufacturer spec.
3. Listen for injector tick: Use a mechanic's stethoscope on each injector body. A dead or irregular tick indicates a stuck or failing solenoid.
4. Check fuel rail pressure: Monitor live fuel rail pressure data via diagnostic tool. Low pressure can mimic injector symptoms and may indicate a fuel pump issue instead.
5. Inspect for external leaks: Check around injector seals for signs of fuel or combustion gas leakage. Black carbon deposits indicate a blown seal.
6. Cylinder balance test: Use diagnostic software to run a cylinder contribution test. This electronically disables each injector in turn to measure its effect on engine speed.

Fault codes linked to CBAB injector issues

• P0201-P0204 – Injector circuit malfunction
• P2146 – Fuel injector group supply voltage

CBAB repair advice

CBAB injectors require IMA coding via VCDS or ODIS after replacement. Torque to manufacturer specification.

CBAB injector replacement cost (UK)

• Per injector: £180 - £350
• Full set: £700 - £1,200
• Labour: £120 - £300

Compatible injector part numbers for CBAB

• Bosch 0445110369 – Bosch solenoid injector for CBAB
• Volkswagen 03L130277J – VW OE reference

Vehicles using the CBAB engine

• Volkswagen Golf Mk6 (2008-2012)
• Audi A3 (2008-2012)
• SEAT Leon (2008-2012)
• Skoda Octavia (2008-2012)

Find your exact CBAB injector by registration

Frequently asked questions

Is the CBAB the same as the CFFB?

No. The CBAB is the earlier common-rail 2.0 TDI (2008-2012). The CFFB is the updated version (2012-2015). They use different injectors.

Do CBAB injectors need coding?

Yes. IMA coding via VCDS or ODIS is required after replacement.

How much does CBAB injector replacement cost?

A set of four remanufactured injectors costs £400-£700. Labour is 2-3 hours.

How much does it cost to replace injectors?

Replacement typically costs £150–£350 per injector depending on brand and engine. A full set of four with professional fitting usually costs £600–£1,200.

Can I drive with a faulty injector?

Driving with a faulty injector can cause engine damage, increased fuel consumption, DPF contamination, and oil dilution. We recommend diagnosis and replacement as soon as possible.

Do new injectors need coding?

Some vehicles require injector coding after replacement using manufacturer-specific diagnostic tools. Many Bosch solenoid units are plug and play. Check your engine guide for specific requirements.