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#1
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1994 E420 Code4 and Code19
Hi,
I did the research on code 19 and know about the chip that Jim has. My questions is that I recently replaced the pipes going to and from the check valve on top of the air pump. Could this cause me to get code 19? Also when the check engine light came on I read the codes from the push button first and got code 4 and code 19. Then I read the codes at pin 4 got back a 1, pin 6 got back a 1, pin 7 got back a 6, and pin 19 got nothing. Is this normal for pin 19? I thought I should have gotten something. What causes code 6 at pin 7? I keep getting this code on that pin. Is there an easier way to clear the codes on all the modules at once? Thank you. |
#2
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Code 6 on EA/CC/ISC is NSS switch contacts on that chassis.
You are not getting any codes on 19 b/c that is DM and DM will not report back any info until the car has done ALL emmissions self-test. That is N/59 Emmissions module and is the same as P/Button that you cleared the codes for CE with. Code 19 coupled with 4 from DM would be b/c of vac leak from AIR system.
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A Dalton |
#3
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The answer to your code 19 and reset question comes with the use of a proper tool. Code 19 is an adaptation code so the obvious answer is to know what your adaptations are! Code 19 occurs when the adaptaions are used up. There are two separate forms of adaptations and the ones that are used up will tell the story. The chip doesn't change anything it just opens up a larger range of adaptation, so larger correctiona can be made by the controller.
A proper tool will clear all codes at once.
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Steve Brotherton Continental Imports Gainesville FL Bosch Master, ASE Master, L1 33 years MB technician |
#4
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I reset all codes and checked the AIR system for leaks. The system is not leaking out of the pipes around the pump. I want to check the small vacuum lines but dont know how to.
Is there a good tool that I can buy? After reseting the codes only code 19 keeps coming back. Code 4 no longer comes back. |
#5
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4wheeling, checkout my main web page about halfway down for info on the 'dreaded' DTC#19 problem.
In any regard you can fix it cheaply. . . ![]() |
#6
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The dreaded code 4 returned. I will check the fuel pressure and the vac lines and report back. Any chance the valve that is by the pump and the one by the washer fluid is bad? If so how do I diagnose them?
Thanks. |
#7
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Here is what I have done so far to diagnose a code4:
I checked the fuel pressure regulator vacuum and it is 20 in Hg. There is no fuel leaking out of it. I still need to check the fuel pressure but I think it is ok as the car idles and runs fine. I checked the vacuum source for the AIR pump it is 20 in Hg. I checked the vacuum input to each one of the vacuum change over valves and they are both at 20 in Hg. I then check the vacuum during a cold start to the diverter valve and it is also 20 in Hg. So up to know I dont have a vacuum issue. The only two things left are the diverter valve and the air injection check valve. How can I figure out which one is faulty? What should I do next? |
#8
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need more info..
Does the pump run? If yes, when it does , does the SOV also open at the same time. ? ..these two questions are basically electrical concerns , as the clutch for the pump and the signal for the SOV require 12v supplied from the ECU. so.. if yes to those 2 questions, you can then procede to air flow and the mechanical sections of the system....do you have vac coming out of the SOV to diverter valve actuating port? If yes , then is that vac actuating the diverter to allow pump air passage? and is the check valve allowing that same air to continue on to the exhaust? That is how the AIR system works and the code comes up when the 02 sensor does nor see or read the lean condition caused by the added air of the pump reaching the cat/exhaust for rapid cat warm-up...that is what the AIR system does and how it is monitored. A No Lean condition at 02 and the code pops #4. Which ONLY means the 02 self test performed by the Emmissions module has FAILED the test. What caused the sensor to not see/read a lean condition can be anything from a blown feed fuse on the supply end of the system [ electrical problem] , to a restriction/non operation at a valve [ mechanical/air flow problem] , to, finally, a possible weak/ bad sensor that is no longer capable to read the extreme lean condition of an otherwise working system . In other words, do you have air originating from a pump and reaching the cat......yes/no/ and why ...that's it. So, that is what you have to find out. It is between those two conditions somewhere and you can only find out by checking upstream/downstream from a common point ...and seperate the electical/mechanical sectors of the system. . It is a chain of components, both electical and mechanical, vac activated, that make up the system and you need to check its logic, step at a time, from the beginning to the end.
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A Dalton Last edited by Arthur Dalton; 09-18-2008 at 08:45 PM. Reason: sp |
#9
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Thank you for your explanation. The last question I promise.
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#10
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Same as any check valve.....one way air flow.
You want exhaust going back up INTO the AIR System when it is not activated or the pressure from the exhaust is more than the pump??????????????????????????? Check valve eliminates that possible.....BUT, you could have a crapped up /stuck check valve that is not functioning ...and that will stop the air flow from the pump from ever reaching where it is supposed to go... I think you get it. It is all about controlled air-flow at pre- warm-up. Emmissions Device .. Be aware that most AIR codes are caused by hose vac leaks or no pump engagement due to fuse, etc....but if those are found to be OK and one has a high milage 02 sensor, that is always suspect as a code 4 can actually be a technical tip-off of an aging/weak 02 sensor ,where the AIR system has in reality nothing wrong with it at all. That is where understanding the realtionships of codes and systems interactions are pragmatic.... In other words, a weak/old sensor that has become less sensitive and lost some range capacity is no longer capable of reading the very lean condition present with AIR system activation and will in effect report an inaccurate finding back to the DM with a perfectly operational AIR system..it is the monitoring 02 sensors sensitivity signal that is faulty, not the system. Kinda like a bad temp gauge telling you the car is running hotter than it actually is...so you go change the thermostat before checking the temp gauge and wind up with the same problem...so then you change the radiator ... nope, that didn't work, etc ....Diagnose Twice, fix it once.... ![]()
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A Dalton Last edited by Arthur Dalton; 09-18-2008 at 10:47 PM. |
#11
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Thanks again for your reply.
The pump does come on and runs for about 2 min on a cold start. The vacuum is also present on the line to the diverter valve. My next step is going to be to see if the diverter valve actually does what it suppose to and after that I will check the check valve. The O2 sensor has about 40000 miles on it. What is the life expectancy of the O2 sensor? Thanks. |
#12
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Bosch rates their O2 sensors for 60K miles . . . . most run them forever.
They can become contaminated by use of products that use "silicone". Read Menu#4a about a "MAF" that was contaminated. That will give you an idea what happens. |
#13
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Something funny happened today. I was double checking the vacuum lines before I returned the rented gauge and the change over valve had no vacuum coming out of it. I think I found my problem. The valve is failing intermittently. I measured the vacuum twice before and it had 20 in Hg of vacuum coming out of it. All the measurements were during AIR pump operation to make sure the valve is energized. So I will replace the valve and report back. Thanks for all your help.
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#14
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They get dirty and hang up..I squirt WD40 into the downstream line and let the vac suck it thru the valve. That clears them up. Same thing happens on the Purge Valves.
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A Dalton |
#15
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I found the source of the problem.
![]() I think this will solve the code 4 problem which I am hoping will solve the code 19 after I reset everything. Thank you all for your help and directions. |
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