unknown CEL...need help

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unknown CEL...need help

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unknown CEL...need help - 2/15/2007 9:53:02 PM

lethalv6

Posts: 13
Joined: 2/15/2007
Status: offline

Hi folks, I am hoping someone can help me figure this one out. I have a 96 protege with the 1.5 and the check engine light is stuck on. I have taken it to 3 different auto stores to have the code pulled and they keep telling me it some "unkown code" but one guys said it had something to do with the fuel system ?
I am not sure if there is a way to pull the codes manually (the old paperclip trick) so I can figure this out myself ? The car idles very bad but never stalls out. I have changed plugs, wires, cap, rotor, 02 sensor, fuel filter, cleaned the tb, and I am out of ideas. The car wont pass emissions with this light on and I am stuck.
any help would be greatly appreciated.
thanks.

Post #: 1

RE: unknown CEL...need help - 2/16/2007 12:53:08 PM

babyhuey

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Joined: 7/28/2005
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What is the code number that was pulled by the part stores lethalv6?? Should start with letter P followed by four numerical digits, for example P0450 or P1455. Some codes are manufacturer specific. A generic scan tool can pull up the correct code # but description is often not accurate.

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Post #: 2

RE: unknown CEL...need help - 2/17/2007 10:34:52 AM

lethalv6

Posts: 13
Joined: 2/15/2007
Status: offline

I finally found a shop that could read the code for me, it came up a P1195 which shows to be a EGR boost sensor circuit ? not sure how this blew out other than age but im sure it will be kind of hard to find. Would something of this nature cause the idle to be as horrible as it is ? its so bad these days the car shakes like crazy when stopped.

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RE: unknown CEL...need help - 2/19/2007 2:58:39 PM

babyhuey

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An 1195 code is in fact indicating a fault in the EGR boost sensor circuit. PCM is either seeing signal of below 0.2 volts or above 4.9 volts when key is first turned to "on" position and it does an initiall self check of the circuit. Could be as simple as sensor connector is unplugged. Would check that out first. Sensor is located in right rear corner of the engine compartment. See first diagram below. Is labeled #1 in either diagram. Could not find a decent diagram of what the boost sensor looks like but it will be right next to a solenoid valve that looks like the one in the second diagram below. Will be a short vacuum tube between the solenoid and sensor. Three wires to the boost sensor will be Gray, Light green w/ Red stripe, and Black w/ Red stripe. If sensor connector is ok then will want to next check voltage inputs and output. Would suspect faulty sensor but if you want to check the voltages and have a voltmeter then will give you specs for what each wire should be reading
Sensor should not have any effect on engine idle. Was the base idle speed checked?

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< Message edited by babyhuey -- 2/19/2007 2:59:41 PM >

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RE: unknown CEL...need help - 2/19/2007 8:06:45 PM

lethalv6

Posts: 13
Joined: 2/15/2007
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Thanks again for all your help on this one bh, I found the boost sensor under the hood and pulled the connectors, cleaned them with elec. cleaner and replaced, then checked the hoses and made sure theres no obstruction...reset ecm and no light now. Im going to see if this works while driving it for a while if not I am guessing its a faulty sensor as you have listed. The idle issue I am completely not sure about, this thing shakes and vibrates so bad you would think its coin operated. I have replaced all "tune up" items, cleaned TB, and still it comes back like this....

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Post #: 5

RE: unknown CEL...need help - 2/21/2007 3:17:23 PM

babyhuey

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Sounds like a good plan with the cleaning, reset and see if CEL come back on.

Was the base idle speed checked and adjusted along with tune items being replaced. Setting base idle/timing involves grounding the TEN pin in the Diagnostic connector to disable PCM override control. Was that done?
Also take a look at the engine and transmission mounts for sagging or being torn. Weak motor/trans mounts are a common problem with excessive idle vibration.

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Post #: 6

RE: unknown CEL...need help - 2/21/2007 3:35:27 PM

lethalv6

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Joined: 2/15/2007
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well I thought I had this one beat, got the light to stay off for about 20 miles then it came back on while the car was running ? I had it checked again and its the same code....but I thought this was a "key on" check....so I assumed it would only fire off when keying the ignition up....not so it would seem. I guess im going to check the boneyards this weekend to see if I can find another 96 that hasnt been pilfered....I just need this thing to pass emissions, then I can play with it some more to get it right. I havent tried resetting the base idle...I will have to try this. The car runs great once your over 1K rpms, its just idling it will shake your fillings loose.
Thanks again for all your input bh, I will let you guys know how this one ends.

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RE: unknown CEL...need help - 2/21/2007 6:25:50 PM

babyhuey

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Well was worth a try anyway lethalv6. Good luck on finding a good uses as a new one will run you just under $300 from dealer. To help expand your search I looked to see what else would be compatable. The same boost sensor is used on the 95-96 Protege with both the 1.5 and 1.8 engines. Is also the same part used on 96-97 626 with the 2.5l V6.

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RE: unknown CEL...need help - 2/22/2007 12:25:58 PM

lethalv6

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Joined: 2/15/2007
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Did I read correctly somewhere on the site that this may have had a TSB issued against it ? I have seearched but found nothing yet.....I know im reaching..haha

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RE: unknown CEL...need help - 2/22/2007 5:03:59 PM

babyhuey

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Joined: 7/28/2005
Status: offline

You know what lethalv6, there might just be one other thing you should check before replacement of the boost sensor. Have never run accross this condition throwing a P1195 code as it would typically always give a P0400 EGR flow malfunction code but you never know.
There is a short vacuum hose connected to the boost sensor. the other end of this hose goes to the solenoid valve right next to it. There is also another vacuum hose on the solenoid that is attached to a port on the intake manifold. With engine running at idle. Pull the vacuum line from the manifold off at the solenoid and make sure that you have good strong intake vacuum. If this is confirmed then reconnect the vacuum hose and remove the other one at the solenoid. Should not have any vacuum at the exposed solenoid port. Now disconnect the electrical connector from the solenoid and apply battery voltage and ground to the two solenoid connector pins. Vacuum should now be felt at the exposed port.
The problem is usually a clogged vacuum port at the intake manifold due to the fact that it is so close to the EGR valve and all of the dirty exhaust gas collect in that area. Let know what you find out.

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Post #: 10