Home » Auto Repair Services » Auto Diagnostic Services

Auto Diagnostic Services

Dupont’s Provides A Variety Of Diagnostic Services Including:

  • Engine Diagnosis
  • Mechanical Diagnosis
  • Electrical Diagnostics
  • Brake System Diagnosis
  • Charging System Diagnosis
Computers have changed the way manufacturers build vehicles. They have also changed the way auto shops diagnose problems. As technology advances, the auto industry will continue to add more and more computers into our cars and trucks.


All modern vehicles have at least one computer built into it. Some modern vehicles have up to 30-40 computers in them. These computer’s provide accurate & instant commands to almost every mechanical or electrical system. This includes: Ignition, Fuel, Emission, Transmission, Brake, Safety Restraint, Navigation & Traction Control.


The engine computer is called the engine control unit or (ECU). Also referred to as the powertrain control module (PCM). Your vehicle has sensors that input raw information to the computer where the data is interpreted and stored.


The number of sensors and computers in your vehicle will differ depending on the year and manufacturer. Using scan tools and laptop computers we are able to run diagnostics on these vehicles.


On-Board Diagnostics (OBD)

When something is not working in your vehicle, a trouble code could be stored in the computer. A warning light could light up on your dashboard. If a light is on your dashboard, A scan tool can be used to retrieve these OBD codes.


Most computer systems will never need maintenance, but if they fail, the system should be diagnosed soon to prevent further damage. Often times the problem is a failed sensor.

In some cases it can be difficult to replicate the problem for your technician. It’s helpful to keep a record of possible symptoms to help the service staff diagnose your problem.


In 1996, OBD (On-board-Diagnostics) was mandated and standardized for emissions and fuel economy systems.


The OBD II system consists of: 

OBD II Data Link Connector & laptop for automotive diagnosis

An OBD II compliant 16 pin Data Link Connector (DLC) & Scan Tool Computer.



Lights and gauges act as potential problem indicators. These lights communicate information to your vehicle’s computer system. If one of your indicator lights turns on, be sure to call Dupont’s at 603-742-8627 so we can diagnose your issue.


Check Engine LightCheck engine light indicator gauge

The check engine light illimuniates if the ECU detects an emission system or engine performance problem.


This could be anything from a loose gas cap to a failing catalytic converter to an engine misfire.


Check the gas cap first.


A check engine light that stays on steady is a sign that serviceis needed. Under most conditions you can still drive the vehicle.However, the longer you drive the more damage you can cause. A blinking light is a sign of a serious problem.


The manufacturer may suggest having the vehicle towed in for repair.Please call us if your check engine light is on or starts flashing so we can make arrangements to get your vehicle in for diagnostics.


Low Fuel IndicatorGas Light gauge indicator light

When the low fuel light turns on, a vehicle may have only a gallon of fuel left. It is best for your vehicle, to refuel before this light ever comes on. It is best to not run your vehicle on low gasoline often because that can lead to premature fuel pump failure.


Oil Pressure Indicator

Do not drive your vehicle if the oil pressure light is on. Low oil pressure can cause immediate engine damage. Check your oil level and add if low. If the light still does not go off, Call Dupont’s for more information before you drive your vehicle. We can discuss whether it can be driven or needs to be towed for diagnosis.

Charging System IndicatorCharging system warning light

The charging system light indicates that the battery is notbeing recharged. This does notnecessarilymean that the battery is malfunctioning. The problem may be another part of the charging system, such as an alternator or a bad connection.


Coolant Temperature IndicatorCooling system warning gauge

If the coolant temperature exceeds the normal range, a warning light will come on, or the indicator gauge will move to the red area. Pull your vehicle over and allow the engine to cool. Serious engine damage could result from driving an overheated engine.


Brake Warning IndicatorBrake Warning Indicator Gauge

If the brake light is on and the parking brake is not engaged, check the brake fluid level. If the fluid level is fine and your brake pedal feels normal, it may be ok to drive your vehicle. Call Dupont’s for diagnosis advice.

Antilock Brake System IndicatorAnti-lock braking system like

If the ABS light comes on, have Dupont’s check for error codes and inspect the brake system. The conventional part of the brake system may still function.