CKFCar Known Faults
SevereAffected: 2012-201540,000–90,000 miles

Vauxhall Astra Astra J 1.6 CDTi 110bhp — DPF Blockage and Regeneration System Failure

DPF blockage is extremely common on the Astra J 1.6 CDTi. The engine's tendency to get stuck in failed regen cycles results in diesel contaminating the engine oil — a serious secondary issue.

Severity

Severe

DIY Difficulty

Moderate

Est. Cost

£200–£1000

OBD Codes

P2452P2453P246C
Component Diagram

DPF

Typical layout and location for the DPF assembly.

DPF diagram
Reference Illustration

Symptoms

  • DPF warning light (amber)
  • Power reduction and restricted performance
  • Oil level above maximum (diesel in oil)
  • P2452/P2453 pressure differential codes
  • Black smoke from exhaust

Root Cause

The 1.6 CDTi's exhaust temperatures struggle to sustain regeneration in urban conditions. Failed active regens inject diesel into the exhaust late in the cycle — this diesel drains past the rings into the oil.

How To Fix

  1. Urgent: check oil for diesel contamination before driving — change if contaminated
  2. Forced regen via Tech2 or compatible OBD tool
  3. If blocked beyond regen: professional clean £200-350
  4. Replacement DPF if internally damaged: £500-1,000
  5. Minimum fix: one 30-min motorway run per week going forward

Estimated Repair Costs

Repair OptionEst. Cost (GBP)
DIY (parts only)£80–£400
Independent Garage£200–£1000
Main Dealership£320–£1600

Other Faults on This Variant

Timing Chain Rattle and Tensioner Failure

Critical
2012-201560,000–120,000 miles£800–£1500

The 1.6 CDTi A16DTH/DTJ engine is notorious for timing chain noise and failure, often from as low as 60,000 miles. This is the most serious known fault on the Astra J diesel.

Clutch Pedal Sticking Down

Severe
2009-201550,000–100,000 miles£150–£700

The clutch pedal fails to return to the top of its travel, often getting stuck halfway or hitting the floor completely.

EGR Cooler Failure and Intake Contamination

Severe
2012-201570,000–130,000 miles£500–£800

EGR cooler failure on the Astra J 1.6 CDTi causes coolant loss and in severe cases, coolant enters the intake manifold. This is a more serious failure than a simple EGR valve block.

Disclaimer: Repair cost estimates are indicative and based on community data. Always get a quote from a qualified mechanic before proceeding with any repair.