Electrical system: alternator
ON CERTAIN PASSENGER VEHICLES, ONE OF THE DIODES USED IN THE ALTERNATOR MAY HAVE BEEN DAMAGED WHEN BUILT. THIS CAN EVENTUALLY RESULT IN FAILURE OF THE DIODE AND AN ELECTRICAL SHORT WHICH COULD MELT THE PLASTIC HOUSING.
NHTSA lists 3 safety recalls and 14 owner complaints for the 1998 Infiniti Q45. Most complaints involve air bags (6) and electrical system (2). The EPA rates it 18 mpg combined.
ON CERTAIN PASSENGER VEHICLES, ONE OF THE DIODES USED IN THE ALTERNATOR MAY HAVE BEEN DAMAGED WHEN BUILT. THIS CAN EVENTUALLY RESULT IN FAILURE OF THE DIODE AND AN ELECTRICAL SHORT WHICH COULD MELT THE PLASTIC HOUSING.
VEHICLE DESCRIPTION: PASSENGER VEHICLES. ONE OF THE DIODES USED IN THE ALTERNATOR MAY HAVE BEEN DAMAGED WHEN BUILT. THIS CAN EVENTUALLY RESULT IN FAILURE OF THE DIODE AND AN ELECTRICAL SHORT WHICH COULD MELT THE PLASTIC HOUSING.
VEHICLE DESRIPTION: PASSENGER VEHICLES. THE IGNITION KEY CAN BE REMOVED WHEN THE ENGINE IS TURNED OFF WITHOUT PLACING THE TRANSMISSION SHIFT LEVER IN THE "PARK" POSITION. THIS DOES NOT COMPLY WITH THE REQUIREMENTS OF FMVSS NO. 102, "TRANSMISSION SHIFT LEVER SEQUENCE, STARTER INTERLOCK, AND TRANSMISSION BRAKING EFFECT."
Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.
“TL* THE CONTACT OWNS A 1998 INFINITI Q45. THE CONTACT STATED THAT THE AIR BAG LIGHT ILLUMINATED. THE DEALER STATED THAT THE AIR BAG WAS FAULTY. THE MANUFACTURER WAS MADE AWARE OF THE ISSUE. THE FAILURE MILEAGE WAS UNKNOWN.”
“WHILE DRIVING ON HIGHWAY VEHICLE SHUTOFF WITHOUT ANY WARNING. AS A RESULT, TO ALTERNATOR MALFUNCTIONED. DEALER CONTACTED.*AK”
“TL* THE CONTACT OWNS A 1998 INFINITI Q45. THE CONTACT INDICATED THAT THE SERVICE ENGINE SENSOR ILLUMINATED AND THERE WAS A LOSS OF POWER. THE CONTACT STATED THAT THE VEHICLE STALLED ON SEVERAL OCCASIONS. THE CONTACT WAS ABLE TO RESTART THE VEHICLE AFTER SEVERAL ATTEMPTS. THE VEHICLE WAS TAKEN TO AN INDEPENDENT REPAIR SHOP WHO WAS NOT ABLE TO REPLICATE OR DIAGNOSE THE FAILURE. THE CONTACT WAS NOT INCLUDED IN RECALL NHTSA CAMPAIGN ID NUMBER: 03V455000 (ENGINE AND ENGINE COOLING). THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 100,000.”
Towing, payload and dimensions aren’t in the EPA or NHTSA data, so we don’t list them.
| Version | City | Hwy | Comb. | Fuel / yr | CO₂ g/mi |
|---|---|---|---|---|---|
| Q45 Auto 4-spd, 8 cyl, 4.1 L · Rear-Wheel Drive | 16 | 22 | 18 | $4,400 | 494 |
| Item | Miles | Time | Note |
|---|---|---|---|
| Engine oil & filter | 5,000–10,000 mi | 6–12 months | Follow the oil-life monitor if fitted |
| Tire rotation | 5,000–7,500 mi | Every oil change | Check pressure monthly |
| Engine air filter | 15,000–30,000 mi | 1–2 years | Sooner in dusty areas |
| Cabin air filter | 15,000–25,000 mi | 1–2 years | |
| Brake fluid | — | 2–3 years | Absorbs moisture over time |
| Coolant | 60,000–100,000 mi | 5–10 years | Long-life coolants last longer |
| Spark plugs | 60,000–100,000 mi | — | Iridium/platinum plugs at the long end |
| 12V battery | — | 3–5 years | Heat shortens battery life |
3 safety recalls as of Oct 30, 2026, according to NHTSA. Recall repairs are free at a dealer. Check your VIN to see whether your car is included and whether the repair was done.
Owners filed 14 complaints with NHTSA. The most-cited components are air bags (6), electrical system (2), engine and engine cooling (1). Complaints are unverified owner reports and aren't adjusted for how many cars were sold.
The EPA rates the 1998 Infiniti Q45 at 18 mpg combined, depending on engine and drivetrain (1 version rated).