I have two problems
I have an 05 liberty and I put in the SEGR about 12 months ago and have had no problems till last week when, I got an check engine light. I checked the code and it was P0403. I cleared the code and put the bypass plug on. drove it for several days with no light. put the SEGR back in and got a light within 10 minutes.
now I did the alterate test that was posted here. I disconnected the 10 ohm resister and connected 12.85 volts to pin 3 ( used 8 D cell battery) ground on pin 6
pin 1 0 volts
pin 2 0 volts
pin 4 .345 volts
pin 7 12.81 volts
pin 8 0 volts
pin 9 12.81 volts

grounded pin 9 and had 12.8 volts on pin 8
put 12.85 volt to pin 1 and had 4.62 volts to pin 2, grounded pin 4 and had 3.15 volts to pin 2 then grounded pin 7 and had 6.22 volts to pin 2
so I believe that it tested out just find.
so does any one have an idea why it is giving me a check engine light?

next problem
after I finished the test I hooked the 10 ohm resister back up and I hooked my test leads back up and swaped the power and ground wires (power to pin 6 and ground to pin 3) yea I let the smoke out. U1 LM324 got hot and smoked. now it is fryed. every thing esle looks good, so is there a chance that some thing else on the board got fryed too. any idea's?

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05 KJ CRD

A better test that puts the MAF input in the proper range is a 4V input to pin 1. With pin 7 open, you should have 3V on pin 2. Then with pin 7 grounded you should have 4V out on pin 2. And with pins 4 and 7 grounded, pin 2 should be 2.4V.

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'05 Liberty CRD B100, SEGR - SOLD

'01 Beetle TDi B100, EGR delete
'83 Mercedes 240D B100, no EGR

--- SEGR Builder ---

Probably both LM339's are cooked as well. All other components should be o.k.

Yes, I bet you are right.

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'05 Liberty CRD B100, SEGR - SOLD

'01 Beetle TDi B100, EGR delete
'83 Mercedes 240D B100, no EGR

--- SEGR Builder ---

well I have replaced the LM324
I did the the test as UFO said. I put 4.5 v to pin 1 got 3v at pin 2. grounded pin 7 and got 4 v at pin 2. grounded pins 4&7 got 3.5 v at pin 2

didn't realy wont to hear that I may have fried both LM339 but neather of them got hot

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05 KJ CRD

If you replaced the 10 ohm resistor, it's likely your battery stack will not drive it for the part of the test where pin 4 is grounded. Everything else should work fine.

For the test with pin 7 grounded and pin 4 not connected, the voltage on pin 1 (you wrote it was 4.5V?) should be the same as the voltage on pin 2. If it's not 4.5V, you may have indeed cooked your LM339s as well -- if you reversed the voltage those suckers are just as sensitive.

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'05 Liberty CRD B100, SEGR - SOLD

'01 Beetle TDi B100, EGR delete
'83 Mercedes 240D B100, no EGR

--- SEGR Builder ---

UFO you may well be right about my battery pack.
man I hate eletronics. you would think after working on helicopter for 35 years I would under stand it better, but it just drives me nuts.
I went and put it back in the jeep and drove it around for 15 minutes and my check engine light never came on.
I will drive it some more tomorrow to see what happens as I know it can't be fixed.
I will probley get 2 of the LM339 and just replace them if the light comes back on. well post what happens next.
thanks for all the help,
I am sure its not over

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05 KJ CRD

well I have drove it for two days now with no problems. I still don't know why I got the engine light as the only thing I have done is replace LM324 that I smoked when I reversed the power wires.
I guest time will tell.
thanks for all the help

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05 KJ CRD

well the day after my last post the engine light came back on. gave code P0101 MAF sencer. so I changed both LM339.
now I drove it for a couble of days and no problem. last night I made a 6 hour drive and after 4 hours on the interstate the light came back on code P0401.
I just tested the box again. useing a 12v lawn mower battery for 12v. and a power supply for the 4v to pin 1.
so I got 12.51 v to pin 3 and 4.0 to pin 1
with pin 7 open pin 2 has 2.98v
pin 7 grounded pin 2 has 4.0v
pins 4 & 7 grounded pin 2 has 4.0
it looks like grounding pin 4 does nothing so what would be the problem?
I will be makeing a 1000 mile round trip next week and would like to have this fixed for the trip

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05 KJ CRD

Is the power resistor still connected? If it is, your power source will not have the ability to really pull pin 4 to 0V. Verify that first. If the resistor is disconnected and grounding pin 4 does not change the output, you may still have an issue with the LM324. The voltage on pin 14 of U1 should follow the voltage you put on pin 4 (0V). But the problem could be in any of the components attached to pin 14 including one of the the LM339s. Inspect the circuit for discolored components and shorts. If you can't find anything and if there is time for shipping, send it to me for repair. I can fix it overnight and get it back to you. Send me a PM if you want to pursue this option.

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'05 Liberty CRD B100, SEGR - SOLD

'01 Beetle TDi B100, EGR delete
'83 Mercedes 240D B100, no EGR

--- SEGR Builder ---

sorry for the delay getting back on here.
I did check it with and with out the power resister connected and got the same reading on pin 2.
pin 14 of U1 did have the same volt as pin 4
I can always just pull the plug on the MAF sencor and live with the light for a while but I think I will leave it connected for a bit to make sure the problem is not some where else.
UFO thanks for the offer but there was not enought time to get it to you and back before I leave. but if you are willing maybe I can still send it to you and let you look at it as I am still at a lost.

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05 KJ CRD