See alot of people take Check Engine Lights (CEL) for granted when they should have some concern as diagnostics has come a long way giving owners a bit more accuracy as far as finding and repairing problems is concerned. As you all may know (and those who dont) that back in 1996 the Automotive Industry was mandated to uniformly standardize and update in respect to emissions system computers, the infomation they monitored and recorded for retrieval later by a certified technician. What that meant to them was that they had to change the way they retrieved, stored and the means by which codes were used in regards to the emissions system and its computer. The mandate standardized the system to be used right down to the port from which the information can be uploaded from the emissions computer and was given the dubious name of OBD (OnBoard Diagnostics, I (pre 96) or II (post 96) both are different in many respects). The codes themselves were also mandated so that basically you could have an import or a domestic and still be able to troubleshoot the issue regardless of make or type of vehicle. OBD ports can be found either under the dash or behind the ashtray (depending on make and model) which makes data retrieval very simple and timely.
Intro:
The main difference in the two types of OBD systems are software related basically because the OBD I system only read if the emissions system was operating or not. The only major shortcoming of this type of diagnostic is the fact that emissions system start to deteriorate slowly. The beauty of the OBD II (the 2nd generation of OBD) is that it is accurate enough to find shortcomings by monitoring more sources of info (sensors and systems), detect errors and save info pertaining to what was happening when the error occured.
Monitoring:
Combined there are two major catergories of monitors used by the OBD II system. Consisting of 11 monitors these two catergories (single and continuos) perform their duty either once every driving cycle (Single) or continously to ensure the computer knows whats happening, when and if it is completed succesfully. The continuos monitors are compromised by the CCM (Comprehensive Component Monitor), Fuel System Monitor and Misfire Monitor while the single monitors are composed of EVAP monitor, AC monitor, Secondary Air System monitor, EGR monitor, Catalyst monitor, Heated Catalyst heater monitor, Oxygen sensor and Oxygen sensor heater monitor.
OBD II Trouble Code decoding:
Basically OBD II system as opposed to OBD I can set aside codes and save them in two catergories which also determines the actions the computer takes to deal with the error. The first type will set off the CEL instantly if an error is detected that is in memory as one that requires the action of the computer to trigger the CEL. For those who are unfortunate to see a flashing CEL there is a serious issue that is occuring that can potentially damage the engine thus requiring immediate/correct action(s) by the opreator. At the sametime the computer is flashing the CEL it will save the appropriate codes involved with the error along with saving the parameters of the engine's operating system as the error is occuring for later retrieval/correction. By parameters i mean that it will save info regarding the fuel system status, fuel ratio :roll: , MAP vacuum :roll: , water temperature, engine load and engine speed. The second type of codes will trigger a different chain of reactions from the OBD computer. At this point the OBD I system wouldnt know what to do but the 2nd generation will detect this type of error and instead of triggering the CEL it will store and monitor this condition waiting for a re-occurance so that the CEL is triggered and again the engine's operating system parameters are saved but if the error doesnt happen again the codes are erased. If the CEL comes on it will stay on until the errors are no longer occuring after three back to back driving cycles. If that happens the CEL goes off and the appropriate codes stored in the computer for 40 cycles to help technicians track and correct the issue. simple as that.
Reading Codes:
When a technician plugs in an OBD II scanner to your car via your OBD port they are given a five digit code (one letter and four numbers) which indicates the system and the type of error the computer has detected in the past or is occuring currently. The letter identifies the system, the first digit identifies a "generic or manufacturer specific" space think dummy letter, the second digit identifies the sub system involved and the final two digits zero in on the eaxct area that failed. Please remember that although there are many tools out there that can read codes only dealership issue scan tools (aka not cheap and very advanced) can read and display parameter snap shots from the OBD computer.
All in all keep in mind that as you "turn up the boost" that your engine computer is there to keep tabs on you and help you by storing and alerting you to detrimental conditions (READ...DETONATION!). So if you happen to get a CEL dont just ignore it get to the bottom of it cause your engine depends on it. Happy boostin!
Intro:
The main difference in the two types of OBD systems are software related basically because the OBD I system only read if the emissions system was operating or not. The only major shortcoming of this type of diagnostic is the fact that emissions system start to deteriorate slowly. The beauty of the OBD II (the 2nd generation of OBD) is that it is accurate enough to find shortcomings by monitoring more sources of info (sensors and systems), detect errors and save info pertaining to what was happening when the error occured.
Monitoring:
Combined there are two major catergories of monitors used by the OBD II system. Consisting of 11 monitors these two catergories (single and continuos) perform their duty either once every driving cycle (Single) or continously to ensure the computer knows whats happening, when and if it is completed succesfully. The continuos monitors are compromised by the CCM (Comprehensive Component Monitor), Fuel System Monitor and Misfire Monitor while the single monitors are composed of EVAP monitor, AC monitor, Secondary Air System monitor, EGR monitor, Catalyst monitor, Heated Catalyst heater monitor, Oxygen sensor and Oxygen sensor heater monitor.
OBD II Trouble Code decoding:
Basically OBD II system as opposed to OBD I can set aside codes and save them in two catergories which also determines the actions the computer takes to deal with the error. The first type will set off the CEL instantly if an error is detected that is in memory as one that requires the action of the computer to trigger the CEL. For those who are unfortunate to see a flashing CEL there is a serious issue that is occuring that can potentially damage the engine thus requiring immediate/correct action(s) by the opreator. At the sametime the computer is flashing the CEL it will save the appropriate codes involved with the error along with saving the parameters of the engine's operating system as the error is occuring for later retrieval/correction. By parameters i mean that it will save info regarding the fuel system status, fuel ratio :roll: , MAP vacuum :roll: , water temperature, engine load and engine speed. The second type of codes will trigger a different chain of reactions from the OBD computer. At this point the OBD I system wouldnt know what to do but the 2nd generation will detect this type of error and instead of triggering the CEL it will store and monitor this condition waiting for a re-occurance so that the CEL is triggered and again the engine's operating system parameters are saved but if the error doesnt happen again the codes are erased. If the CEL comes on it will stay on until the errors are no longer occuring after three back to back driving cycles. If that happens the CEL goes off and the appropriate codes stored in the computer for 40 cycles to help technicians track and correct the issue. simple as that.
Reading Codes:
When a technician plugs in an OBD II scanner to your car via your OBD port they are given a five digit code (one letter and four numbers) which indicates the system and the type of error the computer has detected in the past or is occuring currently. The letter identifies the system, the first digit identifies a "generic or manufacturer specific" space think dummy letter, the second digit identifies the sub system involved and the final two digits zero in on the eaxct area that failed. Please remember that although there are many tools out there that can read codes only dealership issue scan tools (aka not cheap and very advanced) can read and display parameter snap shots from the OBD computer.
All in all keep in mind that as you "turn up the boost" that your engine computer is there to keep tabs on you and help you by storing and alerting you to detrimental conditions (READ...DETONATION!). So if you happen to get a CEL dont just ignore it get to the bottom of it cause your engine depends on it. Happy boostin!
