Glow plug 3 electrical fault.
P0673 — also written PO673, P 0673, 0673 — is the OBD-II code for glow plug 3 circuit. Same code, same fix: this page covers every spelling of it.
Basically, the heating element in cylinder 3 has burned out, leaving that cylinder to fire 'cold' on a frosty morning. It's a classic winter headache for Vauxhall CDTi and VW TDI owners across the UK.
P0673 is a electrical fault code, typically costing £30–£250 to put right in a UK garage.
What P0673 actually feels like to drive
- The 'Coil' light or 'Service Vehicle Soon' message pops up on the dash first thing in the morning.
- Engine sounds like a bag of nails for the first 30 seconds after a cold start.
- Puff of blue/white acrid smoke out the tailpipe when you first fire it up.
- Lumpy, uneven idle that clears up once the coolant needle starts moving.
- Stop/Start system stops working because the ECU is managing a 'priority' fault.
What causes P0673?
- Failed glow plug
- Wiring fault
UK vehicles that throw P0673 most often
- Vauxhall Insignia 2.0 CDTi (A20DTH) 2008-2017
- Volkswagen Golf Mk7 1.6/2.0 TDI (CRBC/CLHA) 2012-2019
- Ford Focus 1.6 TDCi (DV6) 2011-2015
- BMW 320d (N47) 2007-2013
- Nissan Qashqai 1.5 dCi (K9K) 2007-2013
- Volvo V40 1.6 D2 (D4162T) 2012-2015
How P0673 is fixed
- Replace glow plug
The P0673 misdiagnosis that wastes money
I see it every winter: folk assume because the code says 'Circuit', it must be a broken wire or a blown relay, so they start tearing the loom apart or buying a £150 glow plug control module. 95% of the time, it's just the heating element inside the number 3 plug has gone open-circuit. The other mistake is replacing just one plug with a cheap £5 no-name part from eBay. Those cheap ones don't have the same resistance as the Bosch or Beru units the ECU expects, and the light comes right back on. Save yourself the hassle; if one's dead, the others are usually tired too.
What a UK garage should charge for P0673
For a standard Bosch or NGK plug, you're looking at £15-£25 per part. A single-plug swap at an indy garage usually runs about £60-£80 including the diagnostic scan. However, if you've got those fancy 'pressure sensing' plugs found on some Vauxhalls, the part alone is £100+. Labour is usually 1 hour, but it doubles if the access is tight. At a main dealer, expect to pay £150+ per hour labour, often pushing a simple plug change toward the £250 mark. Use Beru or Bosch; avoid the white-box specials if you want the light to stay off.
P0673 repair cost in the UK
Most P0673 repairs land between £30–£250 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Bob's tip on P0673
Before you let any garage touch it, ask them: 'What's your plan if the plug snaps?' If they don't have a hydraulic extraction kit or a specific 'Vibro-motive' tool for stubborn plugs, walk away. To avoid a massive bill, insist they soak the plug in penetrating oil (like PlusGas) for a few days before the job. If they just cold-crank it with a long breaker bar, they'll snap the tip off in the head, and then you're looking at a £1,500 'head-off' job. A good indy will test the resistance at the plug terminal first to confirm it's dead before even putting a socket on it.
Can you drive with P0673?
Yes.
Urgency: low.