Why does my Freightliner Sprinter have glow plug codes and start hard when cold?

Short answer: Glow plug codes on a Sprinter mean either worn glow plugs or a failing glow plug control module. Replace the plugs gently (they snap easily), and if codes for several cylinders return, replace the module. Glow plugs cause hard cold starts but not limp mode.

Symptom: Hard starting or long cranking when cold, smoke at startup, a check engine light, and codes like P0380, P0673 or P0674.

What to check first

1. Read all codes and note which cylinders are listed.
2. Test the glow plugs and the wiring to them.
3. If several cylinders show, suspect the control module.
4. Use penetrating oil and low torque on the plugs so they don't snap.
5. If it's in limp mode, look for other codes with a better scanner.

Likely causes

1. Failed glow plugs. Glow plugs heat each cylinder so a diesel starts when cold. One bad plug sets a code for that cylinder.
2. Glow plug control module. The module powers the plugs. When it fails, several plugs may show as bad. One owner's module was under the battery tray.
3. Wiring or connector. Check the plug connectors and harness before buying parts.

What it usually costs

One owner bought a glow plug module online for about $35 and avoided a $100+ one. Plugs are cheap. Shop prices weren't posted.

Is it safe to keep driving?

Yes. It may start hard in cold weather, but glow plugs don't affect driving once it's running.

DIY or shop?

Yes, for careful DIYers. A snapped plug is a shop job.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA lists 39 recall(s) for the Freightliner Sprinter in these years, and none is for this problem. NHTSA's data for this model was queried for 2007-2018. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. A count is not proof of a defect.
• NHTSA complaints: 12 keyword-matched complaints for Freightliner Sprinter 2007–2018 (of 44 unique complaints queried, NHTSA complaints API by model year, queried 2026-11-05; keywords: start, glow, limp, power, stall, cold). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In Code help please on Reddit r/Sprinters, a 2006 Freightliner Sprinter owner had codes P0673 and P0674 (cylinders 3 and 4 glow plug circuit open) and P0380 on cold starts. Replies said to replace the glow plugs and, if that didn't fix it, the controller. One owner replaced a plug that failed again the next day, then did all the plugs and the controller. Another bought a module online for about $35 that worked for almost a year and warned not to over-tighten the delicate plugs.
• In 2008 sprinter rv limp mode? on Reddit r/Sprinters, a 2008 Dodge Sprinter RV owner replaced one glow plug, then got code P0673 for another. Owners said the plugs and module are easy DIY parts, and that glow plug codes don't cause limp mode, so a limp mode means another fault the basic scanner isn't showing.

Quick tip

Replace the plugs as a set, and swap the module if codes keep moving between cylinders.

Vehicle focus: Freightliner Sprinter diesel, 2003-2018 (sold also as the Dodge and Mercedes-Benz Sprinter).

Safety / mechanic note

A snapped glow plug can damage the engine if pieces fall into the cylinder. Verify with a mechanic.