Siemens VDO / Continental BK2Q-9K546-AG Diesel Injector

On the Ford 2.0 TDCi 4HG / 4HH / 4HJ, a failing BK2Q injector typically presents in three ways. The first is a notable loss of low-end torque — the engine still revs cleanly to 4,000 rpm but pulls noticeably less from 1,500 to 2,500 rpm under load. The second is a steady-state black smoke under hard acceleration in third or fourth gear — atomisation has degraded enough on one cylinder to dump unburnt fuel through the DPF. The third is repeat DPF differential-pressure faults that get cleared at the dealer and return within two thousand miles.

On Defender Puma 2.2 TDCi specifically, the BK2Q failure is often misdiagnosed as a turbo issue because the loss of low-end torque mimics a leaking turbo seal. Run the leak-off test first — a single injector returning visibly more than its three siblings is the unit to replace, and the turbo is fine.

Engine code coverage spans Ford 4HG, 4HH, 4HJ, 4HL, 4HV, P5BT and YN2S (Ford internal designations for the 2.0-litre TDCi pre-EcoBlue family). UK fitment includes Ford Transit Custom / Tourneo Custom 2.0 TDCi 105 / 130 / 155 / 170; Ford Ranger T6 2.2 TDCi (note: 2.2-litre version uses the same body across the BK2Q-9K546-Ax supersession); Ford Ranger PX-II 2.2 TDCi (export); and Land Rover Defender 90 / 110 / 130 Puma 2.2 TDCi 2012-2016.

BK2Q-9K546-AG supersedes the earlier BK2Q-9K546-AB, AC, AD, AE and AF production codes for the same Ford 2.0 / 2.2 TDCi platform. The body and connector pinout are common across the supersession; what changed across the AB→AG production run was the calibration map at the high-load end of the table to keep cylinder-pressure peaks inside the Euro-5 / Euro-6 envelope. Vehicles built before 2014 will accept any AG-suffix unit as a direct fitment replacement.

Ford IDS / FDRS is the only fully-supported toolchain for BK2Q-9K546-AG cylinder-by-cylinder coding on the 4HG / 4HH / 4HJ engine — JLR SDD / Pathfinder handles the Defender Puma 2.2 TDCi side. Aftermarket scanner coverage for this exact ECU calibration is patchy: Autel MaxiSys with the Ford expansion pack works for most 4HG fitments but fails consistently on certain post-facelift Transit Custom Tourneo builds. We recommend pre-booking the coding step with a Ford-aware fitter before the unit ships, particularly for vehicles built after 2014.

Cylinder index on the Transit Custom is straightforward (sequential 1-2-3-4 from the timing-chain end) but on the Defender Puma the layout is reversed — cylinder 1 is at the gearbox end. Get the index wrong on the Defender and the ECU will throw a perfectly-valid P133x cylinder-imbalance code on the wrong cylinder, leading the fitter to chase the wrong injector.

Ford 4HG / 4HH / 4HJ cores arrive with a very specific wear profile because the Transit Custom and Defender Puma applications use a lower-revving driveline than passenger-car DW10 fitments — the cylinder-pressure peaks are lower but the duty cycle is significantly longer. The bench-process for BK2Q therefore runs a long-duration delivery test (45 minutes at mid-range load) rather than the short-cycle delivery test used on DW10 / 6DRH passenger-car families. The long-duration test catches the gradual flow drift typical of fleet-mileage Transit cores — units that pass a short cycle but fail at the 30-minute mark are rejected.

Output is stamped onto the existing BK2Q-9K546-AG body and the bench print-out is held under the order number for two calendar years. Trade-account fleet customers receive matched-bank pricing on four-injector orders for the same Transit Custom or Tourneo Custom chassis.