Is It Safe to Drive With a P0674 Code?
Common Symptoms of a P0674 Fault
P0674 Symptoms at a Glance
Hard cold starting
White smoke at cold start
Rough cold idle
EML on
Possible Causes of P0674
A P0674 code can be triggered by faults across several systems. Identifying the exact root cause requires proper diagnostic equipment and live data — not just reading the code.
Common Causes of P0674
Glow Plug 4 Failure
Glow plug in cylinder 4 has failed.
Glow Plug 4 Wiring Fault
Wiring to cylinder 4 glow plug is damaged.
Connector Fault
Connector to cylinder 4 glow plug.
Control Module Output Fault
Glow plug controller output for cylinder 4.
Why we don't list the exact part: A P0674 code tells you what's happening but not why. Replacing parts without diagnosis is the most common way drivers waste money. A proper diagnosis identifies the specific cause first.
🔍 Get Your Exact Diagnosis
Find Out Exactly What's
Causing Your P0674 — 1st cause free, full report £1.99
Causing Your P0674 — 1st cause free, full report £1.99
MotorLoom cross-references your P0674 against known fault patterns for your exact make, model and mileage — giving you the most likely specific cause, UK repair cost and MOT risk instantly.
Most likely specific cause for your exact vehicle
UK repair cost estimate (parts + labour)
MOT pass/fail risk assessment
Whether it's safe to continue driving
Find Your Problem Now →
First cause free · Full report £1.99 · Instant results
1st cause FREE
Full report £1.99
P0674 and Your MOT
A stored P0674 fault code will cause your car to fail its MOT. The engine management light will be illuminated during the test — an automatic failure. Get the fault diagnosed and repaired, then have the code cleared before booking your test.