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2003 Volkswagen New Beetle Diesel: Fixing P0671 Glow Plug Heater Fault - OBD2 Code Guide

Model: 2003 VOLKSWAGEN NEW BEETLE Fault Code: P0671 Posted: 2010-09-06 17:38

I own a 2003 Volkswagen New Beetle diesel with a 5-speed manual transmission. The check engine light is on, and my OBD2 scan tool has detected code P0671: MOD$0A GLOW PLUG/HEATER CYLINDER 1. What does this mean exactly? Should I replace the glow plug, and if so, which one—starting or heating? I'm not clear on the difference between these functions. Does using remote start impact the glow plug system? My airbag warning light has been on for several months—could that be related to a separate issue, or is it a safety concern requiring professional attention? I'd appreciate any practical advice or troubleshooting steps specific to this model. Are there known common issues with the 2003 New Beetle diesel engine system? Any recommended tools or resources (like wiring diagrams) for accessing the glow plugs or understanding cylinder numbering? Thanks in advance for your help!

Related fault codes
P0671
Comments (4)
Anonymous 2010-09-07 06:49

Inspect the wiring harness connected to Cylinder #1's glow plug. Swap it with a known good glow plug from another cylinder—if the error code moves to the new location, that confirms the faulty glow plug. Replace the unit in that position. Remote start systems do not interfere with glow plug operation and can be safely ignored as a contributing factor. Regarding the airbag warning light: most experts recommend taking it to a certified mechanic for diagnosis. This is a safety-critical system, and DIY repairs are strongly discouraged due to potential risks. Good luck—please update if you find a resolution.

Anonymous 2010-09-07 12:55

Is there an accessible online service manual or wiring diagram showing the glow plug locations? I’ve been researching and noticed confusion about cylinder numbering in older Beetles. Is this information typically included in the owner’s manual? Additionally, I've noticed my driver's side window stops at a certain height and then drops back down—requiring me to manually push it up and pull it to fully raise it. Could this be a simple fix like a motor or linkage issue? Any suggestions for troubleshooting that?

Anonymous 2013-03-04 09:12

Try disconnecting the glow plug wiring harness and cleaning both ends with electrical contact cleaner. Use a cotton swab (with most of the cotton removed) to clean the contacts inside each boot. Reconnect and test—if the code clears, corrosion was likely the cause. If the issue persists, use an ohmmeter: connect the positive lead to one end of a glow plug and negative to ground. Set the meter to 200 ohms. A healthy glow plug should read approximately 0.08 ohms. If any reading is significantly off (more than ±0.05 or 6%), replace that specific plug. Always use the same brand and type as the others—mixing models can cause performance issues and trigger error codes. This method has helped many owners resolve P0671 faults on their 2003 VW New Beetles.

Anonymous 2013-03-04 10:12

Note: This post is quite old—some of the advice may be outdated. Always verify current diagnostic procedures and parts compatibility with updated service manuals or official VW resources.