The readiness monitors simply won't proceed when stuck in error mode any sensor not working or signal not being in the right place at the appointed time upsets the self diagnostic program making an incomplete drive cycle. After insistence from members here to ignore this mechanic and pay someone to replace the thermostat, this member heeded the advice, replaced the thermostat and shortly afterwards had the readiness monitors pass and completed state inspection. This was incorrect and a month went by with no resolution and wasted mileage. A relative (mechanic) insisted that all she had to do was drive several hundred(!?) miles to have the readiness monitors pass. Her coolant sensor was replaced but the temp gauge still indicated at the 1/4 mark. Here's an anology from one S-series post with the infamous ects/thermostat issue.Ī past member posted about not passing emissions inspection due to the readiness monitors being incomplete. Fix the problem and the very next drive cycle will most likely finish as expected. This will cause DTC P0446 to set.Īs far as the drive cycle, the reason for not completing it is because the evap cycle never completed so the diagnostic program is stuck and will not proceed any further until DTC 0446 is resolved. A short to ground causing the EVAP vent solenoid ON, will cause the vent valve to close. If DTC P1640 is set, diagnose that DTC first. DTC P0446 sets when the vacuum decay is too slow indicating a blocked vent system. Once vacuum is obtained, the EVAP vent solenoid is commanded OFF and the vacuum should decrease rapidly. During DTC P0446 diagnostic, the EVAP purge solenoid is commanded to a fixed duty cycle (pulses valve) and the EVAP vent solenoid is commanded ON (closed) in order to build vacuum. The PCM also monitors the EVAP system for small and large leaks. The PCM monitors the EVAP system for circuit faults in the fuel tank pressure sensor, EVAP purge solenoid, and EVAP vent solenoid circuits. ![]() The EVAP system consists of the EVAP canister, fuel tank pressure sensor, EVAP lines and hoses, EVAP purge solenoid (normally closed), EVAP service port, EVAP vent solenoid (normally open), fuel tank, and PCM. The evaporative emission (EVAP) system is used to store fuel vapors as to reduce the amount of unburned fuel from escaping into the atmosphere.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |