Chevy OBD System Codes

Dec 21
09:12

2011

Woody Su

Woody Su

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As we know all cars manufactured after 1996 have to equip with generic second generation On-Board Diagnostics as well as OBD 2 codes specific to cars. Also Chevrolets are without exception.

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As we know all cars manufactured after 1996 have to equip with generic second generation On-Board Diagnostics as well as OBD 2 codes specific to cars. Also Chevrolets are without exception. Chevrolets built before 1996 use special,Chevy OBD System Codes Articles first generation OBD codes specific only to GM cars.

Since 1996, all cars regardless of the make or model use the same basic OBD diagnostic codes. These codes are the same on Fords, Toyotas, Jeeps, Kia, BMW and every other car containing those manufactured by Chevrolet. OBD 2 codes show problems in different areas of the car. These areas are identified by the first character of the code. "P" stands for power train faults; "B" stands for the body problems; "C" stands for chassis electronic malfunctions; and "U" stands for network communication problems. The code will be deferent between OBD2 and OBD 1.

General Motors OBD 2

Chevrolet, Buick, Oldsmobile and GMC are all the subsidiaries of General Motors. While the OBD 2 system was planned to standardized diagnostics, wiggle room was left, permitting manufactures to define extra codes as needed. After all, no two brands of engine are exactly the same. The manufacturer-specific OBD 2 codes use the same format as the generic codes and use the same character prefixes to define the part of the car where the trouble has been detected.

Distinguishing Generic from GM OBD 2

Once trouble codes have been retrieved from a Chevrolet's diagnostic system, there is a method to tell which codes are manufacturer-specific. For power train codes, any code beginning with P1, P30, P31, P32 or P33 is manufacturer-specific. For chassis codes, any code beginning with C1 or C2 is a GM code; GM's network communications codes begin with U1 and U2, and GM-specific body codes all begin with B1 or B2.

General Motors OBD 1

Most Chevrolet cars manufactured before 1995 use a flash code system of OBD 1. The diagnostic system can be placed into self-mode and the error codes within the system will be relayed by a flashing "Check Engine" light. The codes can be diagnosed by counting the number and length of the flashes. GM error codes are two character numbers -- the first number is represented by long flashes and the second by shorter flashes.

How to Access

OBD 2 codes just require a special, handheld OBD code reader or scanner. This device can be bought at most car parts stores. The scanner inserts in to the Chevrolet's data outlet, which is under the driver's side dashboard. Each device differs in how codes are retrieved so it's necessary to look up the scanner user manual for specific instructions. An OBD1 self-test does not use a scanner. Instead, the system can be jumped by connecting the "A" and "B" slots in the car's data port. Then, powering on the electrical system will activate the Check Engine light to begin flashing.