Most common 2003 Infiniti Q45 problems
Share of the 12 complaints; one complaint can involve more than one system. "~" is the median mileage when the problem started.
Infiniti Q45 complaints by model year
Best Q45 years: 2003, 2005, 2001. Years to avoid: 2002. Compare all years →
2003 Infiniti Q45 recalls (1)
Air bags › Side/window
Nissan is recalling certain model year 2003-2005 Infiniti q45 vehicles. A wiring connector for the seat mounted airbag May experience increased electrical resistance, resulting in the non-deployment of the side air bags.
Remedy: Nissan will notify owners, and dealers will modify the wiring connector, free of charge. The safety recall began on March 19, 2012. Owners May contact Nissan customer service at 1-800-647-7261.
NHTSA defect investigations
Federal safety investigators have looked into 2 possible defects involving the 2003 Infiniti Q45:
Side air bag non-deployment
The subject vehicles are equipped with seat-mounted, side torso air bags for the driver and front passenger.this investigation has revealed that faulty side air bag module connectors located under the front seats can cause an interruption in the electrical current that will drop the input voltage below the specified range.as a result, the air bag warning lamp illuminates and the affected side air bag is…
Non-deployment of Side Thorax Air Bags
The subject vehicles are equipped with seat-mounted, side thorax air bags for the driver and front passenger.This investigation revealed that faulty side air bag module electrical connectors located under the driver and front passenger seats can cause an interruption in the electrical circuit that will drop the input voltage below the specified range.As a result, the air bag warning lamp illuminates on the…
What 2003 Infiniti Q45 owners say
Engine & cooling
Start car first thing in the am. Driving normal. Within 5 miles engine shuts off without warning. Loose all power. No code appears. Auto will not start. Finally starts after 5 or 6 tries. This problem has continued to occur every two or three days over the last six months. But auto starts immediately after. Auto and transmission are not performing properly. Now the engine stall while driving is happening on a daily basis. Auto has been checked out at george harte Infiniti, west haven, ct at least five times. Dealership claims they cannot address the problem because no error code appears. Other than this problem, this auto is in excellent condition and should perform satisfactorily for many years to come. There was a recall (Infiniti r3021) that addressed these exact problems, but the dealer service manager claimed that this car was not included. …
Tl* the contact owns a 2003 Infiniti Q45. While driving 35 MPH, the vehicle stalled and the service engine warning indicator illuminated. The contact was able to restart the vehicle after several attempts. The vehicle was taken to an independent mechanic where it was diagnosed that the camshaft position sensor failed and needed replacement. The vehicle was not repaired. The dealer was not contacted. The manufacturer was made aware of the failure and informed the contact that the VIN was not included in NHTSA campaign number: 03V455000 (engine and engine cooling). The failure mileage was approximately 150,000.
Electrical system
Tl* the contact owns a 2003 Infiniti Q45. While driving various speeds, the engine stalled without warning and all power was lost. After several attempts, the vehicle was able to restart. The failure recurred randomly. The vehicle was taken to a dealer where the failure could not be determined. The vehicle was not repaired. The manufacturer was notified of the failure. The failure mileage was approximately 61,000. Updated 11/29/16 the consumer has since traded the vehicle. Updated 12/06/16.
My 2003 Infiniti Q45 repeatedly stalls [so far, 15+ times] and often will not restart [10+ times]. With my family and me in the car, the stalling of the car puts us repeatedly in jeopardy of a rear-end collision or vandalism or bodily injury in dangerous areas. The car is properly maintained on its service schedule. It took my mechanic a week at a cost of $90 to confirm that the problem is the engine control module [ECM], the 'brain' of the car which controls other vehicle sensors, and this was confirmed by the Infiniti dealer at a cost of $150. The ECM was sent to texas for reconditioning and reprogramming, but is being returned because the ECM is irreparable. The cost to buy and reprogram a new ECM from Infiniti, the only source, is $2000 for a vehicle with 100,000+ miles. But a new ECM will likely have the same problems as the ECM being replaced. …
Steering
Tl* the contact owns a 2003 Infiniti Q45. The contact stated that while driving at 30 MPH, a noise emitted from the front of the vehicle. The vehicle was taken to a dealer. The technician diagnosed that the fan belt and power steering belt needed to be replaced. The vehicle was repaired. In addition, three months later, the vehicle failed to start. The vehicle was taken back to the dealer. The vehicle was not diagnosed or repaired. The failure recurred on numerous occasions. The manufacturer was not notified of the failure. The failure mileage was 92,000. The VIN was unavailable.
Tl* the contact owns a 2003 Infiniti Q45. The contact stated that while driving 35 MPH, the steering wheel seized and there was a sudden loss of power. The vehicle was able to restart and resumed to normal. The failure occurred on three occasions. The dealer repaired the vehicle but the failure recurred. The manufacturer was not made aware of the failure. The failure mileage was 80,000 and the current mileage was 97,000.
2003 Infiniti Q45 engines & fuel economy
| Engine | Transmission | Drive | MPG city / hwy / combined |
|---|---|---|---|
| 4.5L 8-cyl | 5-speed automatic | RWD | 16 / 22 / 18 |
EPA ratings. Class: Large car.
Frequently asked questions
Is the 2003 Infiniti Q45 a good car?
Based on 12 owner complaints filed with NHTSA, the 2003 Q45 rates average: 56% fewer complaints than a typical year of the Q45 at the same age. It is one of the best Q45 years by this measure. Complaint counts don't account for sales volume or individual maintenance, so have any used car inspected before buying.
What is the most common problem with the 2003 Infiniti Q45?
The engine & cooling — 7 complaints, 58% of all complaints for this model year. Next are the electrical system (3) and steering (3).
How many recalls does the 2003 Infiniti Q45 have?
There is 1 recall for the 2003 Infiniti Q45, the most recent from February 28, 2012 (side/window). Recall repairs are free at any authorized dealer — check whether yours has been done with the VIN recall check.
What are the best and worst years of the Infiniti Q45?
The best years by complaints, compared at the same age, are 2003, 2005 and 2001. Years to avoid or approach with caution: 2002. See the full Infiniti Q45 years comparison.
At what mileage do 2003 Infiniti Q45 problems happen?
The median mileage reported in complaints is about 100,000 miles; 9% of problems with a recorded mileage started before 50,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.