![]() The Bureau of Automotive Repair recognizes that competing the EVAP monitor can be difficult, so your 2003 Silverado will pass the OBD II portion of the smog inspection with an incomplete EVAP monitor if the “Check Engine” (MIL, Service Engine…, etc) is not commanded on, and all other monitors are complete. Again, don’t press the clutch or brakes or shift gears. This will perform the same diagnostics as in step 5. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. Hold a steady speed of 88km/hr (55mph) for five minutes. This will perform the same diagnostics as in step 3. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). ![]() During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. ![]() During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. This will test the O2 heater, Passive Air, Purge “No Flow”, Misfire and if closed loop is achieved, Fuel Trim. The more electrical load you can apply the better. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run. In order to be classified as a cold start the engine coolant temperature must be below 50☌ (122☏) and within 6☌ (11☏) of the ambient air temperature at startup. To perform an OBDII Driving cycle do the following: A complete driving cycle can be done in under fifteen minutes. If the PCM doesn’t recognize the voltage change from the switch at the appropriate conditions, it will set one of several DTCs.The following is the recommended driving cycle for General Motors.Ī complete driving cycle should perform diagnostics on all systems. In this condition, the PCM also recognizes that the system is sealed and passes the test. The vacuum overcomes the spring tension in the diaphragm to close the contacts in the switch. As the engine cools, the EVAP system builds vacuum. Second, when the engine is shut off after running at operating temperature, the PCM performs a small leak test. When the switch closes, the PCM recognizes that the system is sealed and then passes the test. If the EVAP system is sealed, the pressure overcomes the spring tension in the diaphragm to close the contacts in the switch. First, when the vehicle is running, the EVAP system is pressurized due to natural vapor pressure. The PCM uses the ESIM in several conditions. At this point the contacts in the ESIM will close and report back to the PCM that the system is sealed. After the vehicle is parked and the fuel begins to cool down, if the tank and the EVAP system are sealed, a vacuum should be drawn on the system. Imagine the vehicle moving around and fuel sloshing around or sitting in the sun all day. The Chrysler ESIM is essentially a switch that closes when the vacuum in the tank exceeds a specific pressure (typically 1” H 2O). Whereas many manufacturers rely on some form of a purge and seal/vacuum decay for their EVAP system self-tests, Chrysler has relied on some form of natural vacuum leak detection for several decades now. Best practices for working on Chrysler ESIM systemsĬhrysler Evaporative System Integrity Monitor (ESIM) have been used since the late 2000’s, but due to their unique characteristics they may provide some diagnostic challenges for technicians.
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