Diagnostic Trouble Codes

What are they?

Shade Tree Garage is a NJ-Certified Emissions Repair Facility. When you bring your vehicle to us for its emissions inspection, there used to be a process of using a tailpipe probe to measure the emissions from your vehicle. Now, we plug into the On Board Diagnostic (OBD) connector and ask your car if it has been running clean.

If the check engine lamp isn’t on you will probably pass inspection. If the lamp is on, the computer in the car will “turn you in” as being non-compliant with emission regulations. On the Vehicle Inspection Report (VIR) there will be codes describing a failure and with that will be a wealth of data inside the computer for the technician to be able to determine and correct the problem so your car will receive a “clean” bill of health.

Here are some of the DTC codes and their descriptions:

  • P0300, P0301,P0302, P0303, P0304, P0305, P0306 are all cylinder misfire codes with the last digit identifying the specific cylinder.
  • P0128, P0325,P0340, P0171, P0174 are all engine or fuel trim codes.
  • P0400, P0401, P0410, P0420, P0421, P0430, P0441, P0446, P0456 are related to catalytic converters or exhaust system issues.
  • P0455, P0442, P0440, P441,P0446, P0456 are related to fuel vapors escaping to the atmosphere with P0456 being the one when a gas cap is left off.
  • P1131, P0133, P0134, P0135, P0136, P0138, P0155, P0161 all relate to oxygen sensors.

If your car failed emissions tests or you need to have an emissions inspection performed on your vehicle in New Jersey, call Shade Tree Garage today at 973-540-9880 or contact us on-line.