Clearing Diagnostic Codes 2005 Dodge Caravan
Posted October 8, 2011 at 09:42 pm
Posted October 9, 2011 at 03:06 am
Auto parts stores around here will not erase a code for you, even if you ask them to (probably because of legal liability and lessons learned from lawsuits).
If the light stays out, you have nothing to worry about. The OBD II state emission test looks for various emission monitors that the PCM tests as being passed. A vehicle won't pass a state test immediately after a fault goes away because the OBD II monitprs have to run first. After the monitors run and pass their tests, the vehicle will pass the state test. It takes about 3 'good trips' (warm-ups, cool-downs and drive-cycles) to run the emission monitor tests. The monitor test results are lost with a battery disconnect. The fuel tank has to be over a 1/4 full and the speedometer signal needs to be present in order to run the monitors.
I think that the PCM tests the EGR action by turning on the EGR valve while watching the MAP for a vacuum drop under conditions determined by the PCM software. This is done invisibly to the driver.
Posted October 9, 2011 at 02:22 pm