P0675: Cylinder 5 Glow Plug Circuit

What it means

An electrical fault is present in the glow plug circuit for cylinder 5. The glow plug control module cannot drive this plug correctly — open circuit, short, or out-of-range resistance — so cylinder 5 is not pre-heated. On a cold start this causes hard starting, white smoke, and a misfire-like rough run until the engine warms. Causes: a failed glow plug, a broken supply lead to that plug, corrosion at the plug connector, or a faulty module output for cylinder 5.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

The cylinder 5 glow plug warms that cylinder to help a diesel engine start and run cleanly while cold; the glow plug control module switches power to it. P0675 sets when the module detects an electrical fault on the cylinder 5 glow plug circuit, such as an open, short, or resistance beyond the manufacturer’s specification. The code identifies cylinder 5’s branch, not a whole-bank fault.

Common causes

Most likely first.

1. Failed cylinder 5 glow plug
2. Open or shorted wiring to the plug
3. Corroded or loose connector
4. Glow plug control module output fault

Symptoms

• Glow plug warning light on (often orange coil symbol)
• Hard cold start or no start in cold weather
• White smoke from exhaust during warm-up

How to diagnose it

1. Save freeze-frame data and scan for other glow-plug circuit codes to see whether the issue is confined to cylinder 5.
2. Confirm cylinder 5’s location from service information, then inspect its glow plug terminal, connector, and lead for corrosion, loose fit, or harness damage.
3. With the circuit isolated according to the manufacturer’s procedure, measure the cylinder 5 glow plug and compare it with the manufacturer’s specification.
4. Test the cylinder 5 wire for continuity and shorts, including at the module connector.
5. If the glow plug and wire are sound, check the module output for cylinder 5 using the specified test method.
6. Clear the code after repair and recheck it following a cold start.

Common fixes

• Reseat or clean the cylinder 5 glow plug connector.
• Repair damaged cylinder 5 wiring or connector terminals.
• Replace the cylinder 5 glow plug if it fails its electrical or function test.
• Repair or replace the module’s cylinder 5 channel if its output fails with good wiring and plug.

Can I keep driving?

Driving may be possible if the engine runs smoothly when warm, but cold starts can be difficult and may bring rough running or white exhaust smoke. Avoid repeated cranking, and repair the fault if symptoms worsen or cold starting becomes unreliable.