This vacuum line is mounted to the radiator plastic shroud and it is vented to the atmosphere and while checking it out noticed it has a leak down by the steering gear box. Could this be the vent to the evap system that has a yellow light and a blinking evap monitor now for three drive cycles and 15 cold warm ups so far without any hard code just the yellow light and the evap im flashing.Can anybody help me with this evap issue does it really take 40 warm ups as said in the innova manual.My blazer 4x4 is a 2003 L/S 4.3 liter.And tomorrow I will fix the vacuum leak and see if that makes any difference on the evap im constantly blinking with out leaving any hard code.

 

The vent line on the fan shroud is for the front differential. Nothing to do with EVAP.
The yellow light is flashing.... is this on the dash or on your Innova?


What kind of problem with the EVAP system? Is the check engine light on? Are there any pending DTC's?

 

Yes the yellow light is on the innova tester the evap IM is flashing with no hard codes or freeze frames and in the innova manual it calls for three drive cycles witch I have done with no change also it calls for 40 warm ups I changed a gas cap a year or so ago and it took the better part of a week and a half plus two trips to Tacoma and two trips to Burien.To have the evap IM run its course and stop flashing.

 

The PCM continuously monitors certain circuits, and others are monitored only when certain driving patterns are duplicated, those are called "monitors". The monitors run and complete their tests under normal driving conditions, but the pattern is very specific and it must be perfectly duplicated. Some monitors require a more involved pattern than others and they can take substantially longer to run and complete, (EVAP is one of them). Performing the General Motors Driving Cycle will force all of the monitors to run and complete their tests. If the steps are not performed exactly as written, the test will not run and complete. If a fault is detected after the test is complete, the check engine light will illuminate and a DTC will be set in memory. If a particular test does not complete, depending on how the scan tool was programmed, the "IM" status will show "INC", "incomplete", "not run" etc etc. With your Innova, apparently it is programmed to flash a light.


Before performing the drive cycle, it is important to clear all three memories in the PCM: Current faults, history files, and pending files. Generally it requires a higher end scan tool to clear all 3 memories. Most "entry level" scan tools, (under ~$1K) can not do it). Each step must be performed exactly as written. The steps do not need to be done in order, but each step must be performed for all of the monitors to run and complete their tests. With careful planning, and some practice, the drive cycle can be completed in about 20 minutes. If a monitor indicates incomplete after performing the cycle, the drive cycle was not performed exactly as written, (operator error) try again

 

Yes I looked up the GM drive cycle and completed three of them .Start car cold turn on all electrical let run for 2 and 1/2 minutes shut off all electric then accelerate to 55 mph for 3 minutes coast down to 20 mph then accelerate to 55 mph for 5 minutes then coast down to 20 mph this should complete the drive cycle.And the yellow light is on steady the IM is flashing for the evap system.? does it take the drive cycles +40 warm ups to clear the flashing evap icon.

 

Nope, drive cycle alone is all it takes. Where the 40 warm ups comes into play, is with certain DTC's, (not all) if the problem is not present for 40 consecutive warm ups, the DTC will automatically clear from memory. If any monitor is incomplete after the drive cycle, the drive cycle was not performed correctly. When the drive cycle is performed correctly, it forces all of the monitors to run and complete all of their tests.


If the check engine light is on steady, there is a hard fault present. It must be repaired, all memories cleared, and the drive cycle performed correctly to confirm the repair.

 

OK CAPTAIN HOOK Here is the OBD2 reference table.
A monitor type how often the monitor run continuous once per trip.
B number of trips needed with a fault present to set a pending DTC
C number of consecutive trips needed with a fault present to command the MIL ON and store a DTC
D Number of trips needed with no faults present ,to erase a pending DTC
E Number and type of trips or drive cycles with no faults present to turn off the MIL
F Number of warm up periods needed to erase the DTC from the computers memory after the MIL is turned off
F is the only one that fits the symptoms and category
A B C D E F

EVAP SYSTEM

once per trip 1 2 1 3 trips 40

 

The list explains what the PCM needs to see, and how it reacts, with regard to different DTC's. There are 3 different categories of DTC's, and each one has it's own set of requirements for setting and clearing itself. Some DTC's never clear automatically and must be manually cleared.

The check engine light must be off, and all memories must be cleared, before starting the drive cycle.
Did you clear the memories before starting the drive cycle?
Did the check engine light remain off before, during, and after the drive cycle, (with all monitors complete)?
If the check engine light came back on, what DTC's are in memory?

 

Answer to your question.There was a code PO117 bank 1 to lean and the check engine light was on.But on the second drive it turned off the check engine light its self the code PO117 was still in memory so I cleared it with my innova tool and the freeze frame that is when the innova yellow light came on and the evap IM began to flash and after 4 gm drive cycles and 15 warm ups it is still flashing.Is there another way to erase the OBD memory or will it require the 40 warm ups.Because there is no check engine light or any hard codes displaying when hooking up the innova tester just the yellow light and the flashing for the EVAP IM all other IM,s run and stop flashing.

 

Clearing all memories removes all DTC's from the memories and resets the monitors.
If the IM status on the scanner indicates a monitor is incomplete after the drive cycle, the cycle was not performed correctly. According to your scanner, the EVAP monitor has not run and completed its tests. If you perform one drive cycle correctly, all monitors will run and complete their tests, (all monitors will indicate "complete" or "ready"). If the check engine light on the dash remains off after the drive cycle, you're done. Don't pay too much attention to the warm up cycles, it's basically "information only". If you do the drive cycle correctly, exactly as written, all monitors will indicate complete, and the check engine light will remain off.


If the check engine light comes on before, during, or after the drive cycle, the DTC must be diagnosed and repaired, the memories cleared, and another successful drive cycle performed. If the light comes on again, the process needs to be repeated.