Auto Diagnostic Services

Vehicle DiagnosticsDupont’s Provides A Variety Of Diagnostic Services Including:

  • Engine Diagnosis
  • Mechanical Diagnosis
  • Electrical Diagnosis
  • Brake System Diagnosis
  • Charging System Diagnosis

Transmission Diagnostics 

Dupont’s recommends transmission diagnostics when:

  • You have a shake or stutter upon acceleration.
  • Any kind of harsh shifting.
  • If you are giving the vehicle gas and it’s not accelerating.
  • If your vehicle is getting stuck in gear or not shifting.
  • The clutch pedal will not release.
  • Ticking noise when the clutch is pressed.
  • Red or clear fluid leaking on the ground.

We start by scanning for any trouble codes. We check fluid levels as well as various components of the transmission.

Electrical Diagnosis

Dupont’s recommends electrical diagnostics when:

  • The battery light is on.
  • Your vehicle will not start.
  • Any electrical components will not function as intended.

We start with a basic charging systems check. From here we continue to check the battery, alternate and starter. We always follow the manufacturers recommended steps when diagnosing a problem.

Engine Diagnostics 

Engine diagnostics is recommended when you have a check engine light. Ask for engine diagnostics if you are experiencing a stutter or hiccup when idling or driving & any odd noises or rattles should be diagnosed.

We perform engine diagnostics by scanning for trouble codes. We check your service information to make sure you haven’t missed a major service. Throughout the process, we follow the manufacturers recommended steps to diagnosing your engine problem.

Brake System Diagnostics 

We recommend you have your brakes diagnosed when your:

  • Feeling a pulsation when braking.
  • Hearing a grinding sound when braking.
  • Brake light, ABS light or TCS light is on.
  • Brakes feel spongy or soft.
  • Hearing loud noises when coming to a stop.

We start diagnosing your brake problem by removing all four wheels, calipers & rotors. We inspect the entire braking system including various components and functionality.

The Technical Side of Diagnostics

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 to 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 computers 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 illuminates 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.

If the light stays on steady it’s a sign that service is 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.

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 not being recharged. This does not necessarily mean 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.