P0671 on Mercedes-Benz
Cylinder 1 Glow Plug Circuit
P0671 on Mercedes-Benz vehicles indicates cylinder 1 glow plug circuit. Au7o has documented this code across 1 Mercedes-Benz model — most commonly on Sprinter. This is a diesel engine code. Glow plugs are small heating elements that warm each cylinder's combustion chamber so a diesel engine can start easily, especially in cold weather. P0671 means the engine computer (through the glow plug control module) detected an electrical fault in the circuit for the cylinder 1 glow plug — typically an open circuit, a short, or resistance that's out of the expected range. The most noticeable effect is harder cold starting, rough running until warm, or increased white exhaust smoke on startup. Typical repair costs on Mercedes-Benz range from $300 to $1,500, depending on the specific model and root cause.
Common Causes of P0671
- •Failed (open or shorted) cylinder 1 glow plug
- •Damaged or corroded glow plug wiring/connector
- •Loose or corroded glow plug terminal/strap
- •Faulty glow plug relay or control module
- •Broken or chafed harness to the glow plug
- •Poor ground or supply voltage to the glow plug circuit
P0671 on Mercedes-Benz by Model
Mercedes-Benz Sprinter(1 issue)
- Glow Plug Failure and Cold Start Issues2007-2025
Sprinter glow plugs fail with age, causing hard starting in cold weather, rough idle when cold, and white smoke on startup. The OM642 V6 is particularly prone to glow plug seizure in the cylinder head, making removal difficult and risking broken glow plugs that require cylinder head removal to extract.
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View P0671 across all makes →Frequently Asked Questions
What does P0671 mean on Mercedes-Benz?▼
P0671 stands for "Cylinder 1 Glow Plug Circuit." This is a diesel engine code. Glow plugs are small heating elements that warm each cylinder's combustion chamber so a diesel engine can start easily, especially in cold weather. P0671 means the engine computer (through the glow plug control module) detected an electrical fault in the circuit for the cylinder 1 glow plug — typically an open circuit, a short, or resistance that's out of the expected range. The most noticeable effect is harder cold starting, rough running until warm, or increased white exhaust smoke on startup. On Mercedes-Benz specifically, this code is documented across 1 model.
What causes P0671 on Mercedes-Benz vehicles?▼
Common causes on Mercedes-Benz: Failed (open or shorted) cylinder 1 glow plug, Damaged or corroded glow plug wiring/connector, Loose or corroded glow plug terminal/strap, Faulty glow plug relay or control module, Broken or chafed harness to the glow plug. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0671 on a Mercedes-Benz?▼
Repair costs on Mercedes-Benz range from $300 to $1,500, depending on the specific model and root cause.
Which Mercedes-Benz models have P0671 documented?▼
Au7o has documented P0671 on 1 Mercedes-Benz model: Sprinter.