On most UK diesels (VAG, PSA, Ford) this points to the glow plug control circuit, so the plugs are not heating properly for a cold start. On some older petrol engines the same code relates to the ignition coil driver instead.
P1351 — also written P1351, P 1351, 1351 — is the OBD-II code for glow plug / ignition coil control circuit. Same code, same fix: this page covers every spelling of it.
P1351 is a ignition fault code, typically costing £90–£550 to put right in a UK garage.
What causes P1351?
- One or more failed glow plugs
- Faulty glow plug control module or relay
- Corroded glow plug wiring or connectors
- Blown glow plug fuse
How P1351 is fixed
- Resistance-test each glow plug
- Check the control module supply and output
- Replace failed plugs carefully — seized ones need heat and patience, not force
- Repair corroded wiring
P1351 repair cost in the UK
Most P1351 repairs land between £90–£550 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.
Can you drive with P1351?
Yes in mild weather. Expect hard cold starts, white smoke and rough running until it warms up.
Urgency: medium.
What P1351 is telling you
Ignition codes are logged from crankshaft speed. The ECU watches how evenly the crank accelerates between firing events, and a cylinder that contributes less than its neighbours is flagged before the driver notices anything.
On P1351 specifically — glow plug / ignition coil control circuit — the stored code records the moment that check failed, not the moment the part gave up. That gap is why two cars with the same code can need completely different repairs.
How P1351 is diagnosed properly
Each of the known causes is ruled in or out in cost order, cheapest and most likely first. On P1351 that means working through them like this:
- One or more failed glow plugs — confirmed with live data before any part is bought.
- Faulty glow plug control module or relay — checked for outstanding manufacturer updates before any hardware is touched.
- Corroded glow plug wiring or connectors — checked with the loom flexed and the engine warm, because a wiring fault that is intermittent when cold shows itself under heat and vibration.
- Blown glow plug fuse — confirmed with live data before any part is bought.
An hour of diagnostic time on P1351 routinely saves more than it costs, because the alternative is buying the most expensive part on that list and hoping.
The repairs that actually clear P1351
- Resistance-test each glow plug
- Check the control module supply and output
- Replace failed plugs carefully — seized ones need heat and patience, not force
- Repair corroded wiring
After the repair the code is cleared and the car is driven until the relevant readiness monitor completes, rather than handed back as soon as the light goes out. A code that has only been erased will come straight back on the next drive cycle.
What happens if P1351 is ignored
It is drivable in the short term. Left for months, though, the secondary damage is what costs money, and the original cheap cause is still there underneath it.
For reference, P1351 typically lands at £90–£550 all-in at an independent garage in the UK — main-dealer quotes for the same job usually sit above that.
Getting P1351 looked at
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P1351 is showing on your car, bring the scan results with you — we will read the live data ourselves, tell you which of the causes above it actually is, and price the repair before any work starts.