The On-Board Diagnostics II (OBD2) port in your 2004 Volkswagen Jetta is essential for diagnosing vehicle issues. Mechanics and car owners alike rely on this port to connect diagnostic tools and read trouble codes, helping pinpoint problems quickly and efficiently. If you’re experiencing issues connecting to your OBD2 port with a scanner, a blown fuse might be the culprit. Specifically for a 2004 Jetta, the fuse related to the OBD2 port is often Fuse 12.
This guide will help you locate the OBD2 port fuse in your 2004 Jetta and understand the fuse box layout for your vehicle. Knowing this information can save you time and potentially money by allowing you to perform basic troubleshooting before seeking professional help.
Locating the OBD2 Port Fuse in a 2004 Jetta
In the MKIV generation Volkswagen Jetta, including the 2004 model year, the fuse box is typically located inside the cabin, on the driver’s side. You’ll usually find it behind a panel on the left side of the dashboard, often near the steering wheel or the driver’s side door.
Once you’ve located the fuse box, you’ll need to identify Fuse 12. According to the fuse diagram for MKIV Jettas, Fuse 12 (7.5A) in the top section of the fuse box is designated for the Data Link Connector (DLC) power supply, which is your OBD2 port.
It’s always a good practice to check the fuse even if it looks visually intact. Sometimes, a fuse can be blown internally without a clear visible break. Replacing Fuse 12 with a new 7.5 amp fuse is a simple first step in troubleshooting OBD2 port issues on your 2004 Jetta.
MKIV Jetta Fuse List for Reference
For a more comprehensive understanding of your 2004 Jetta’s electrical system, here is a detailed fuse list for the MKIV generation. While you’re checking Fuse 12 for your 2004 Jetta Obd2 Port, you might find this complete list helpful for other electrical troubleshooting needs.
MKIV Fuse List
Top Section (Left to Right by Column)
- Washer nozzle heaters, glove compartment light, memory seat control module (10A)
- Turn signal lights (10A)
- Fog light relay, instrument panel light dimmer switch (5A)
- License plate light (5A)
- Comfort system, cruise control, Climatronic, A/C, heated seat control modules, automatic day/night interior mirror, control module for multi-function steering wheel, control unit in steering wheel (7.5A)
- Central locking system (5A)
- Back-up lights, speedometer vehicle speed sensor (VSS) (10A)
- Open
- Anti-lock brake system (ABS) (5A)
- Engine control module (ECM): gasoline engine (10A); diesel engine, Model Year 2000 > (5A)
- Instrument cluster, shift lock solenoid (5A)
- Data Link Connector (DLC) power supply (7.5A) – OBD2 Port Fuse
- Brake tail lights (10A)
- Interior lights, central locking system (10A)
- Instrument cluster, transmission control module (TCM) (5A)
- A/C clutch, after-run coolant pump (10A)
- Open
- Headlight high beam, right (10A)
- Headlight high beam, left (10A)
- Headlight low beam, right (15A)
- Headlight low beam, left (15A)
- Parking lights right, side marker right (5A)
- Parking lights left, side marker left (5A)
Bottom Section (Left to Right by Column)
- Windshield and rear window washer pump, windshield wiper motor (20A)
- Fresh air blower, Climatronic, A/C (25A)
- Rear window defogger (25A)
- Motor for rear windshield wiper (15A)
- Fuel pump (FP) (15A)
- Engine control module (ECM) gasoline engine (15A); diesel engine (10A)
- Power sunroof control module (20A)
- Transmission control module (TCM) (20A)
- Injectors: gasoline engine (10A); diesel engine (15A)
- Headlight washer system (20A). Open
- Engine control elements (10A)
- 12 V power outlet (in luggage compartment) (30A)
- Fog lights (15A)
- Terminal (86S) on radio, Instrument cluster (10A)
- Central locking system (with power windows), luggage compartment light, remote/fuel tank door, motor to unlock rear lid (15A)
- Emergency flashers (15A)
- Dual tone horn (20A)
- Cigarette lighter (15A)
- Radio (25A)
- Engine control elements (10A)
- Heated seats (15A)
Fuse Arrangements in Fuse Bracket/Battery:
- S162. Glow plugs (coolant) (50A)
- S163. Fuel pump (FP) relay/glow plug relay (50A)
- S164. Coolant fan control (FC) control module/coolant fan (40A)
- S176. Relays panel interior (110A)
- S177. Generator (GEN) (90 Amp.) (110A). Generator (GEN) (120 Amp.) (150A)
- S178. ABS (hydraulic pumps) (30A)
- S179. ABS (30A)
- S180. Coolant fan (30A)
Conclusion
Troubleshooting your 2004 Jetta’s OBD2 port issues can start with a simple fuse check. By locating Fuse 12 in your fuse box and ensuring it’s in good condition, you can rule out a common problem. This guide, along with the complete MKIV Jetta fuse list, equips you with the essential information to maintain and understand your vehicle’s electrical system. Remember to always consult your vehicle’s owner manual for the most accurate fuse box diagrams and specifications related to your specific 2004 Jetta model.
