Unplugging MAF Question

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Hi,
If my MAF is pulled, what codes should I see when I ran a scan?

I ran a scan just before I installed my SEGR and had two codes. The same two codes are there status/post SEGR install. Would appreciate help in figuring out what codes would unplugging the MAF throw and if my SEGR is working-I don't think it is.

Thanks,
Drew

gmctd · **Posted:** Sat Aug 02, 2008 9:09 pm

Are the codes secret? Any reason you're not posting them?

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Sorry, they aren't secret.

The codes I had were P1140 and P0102 just prior and post SEGR. Should a person have two codes with MAF unplugged is there something wrong with my wife's CRD. We've been driving it with MAF unplugged for a year or so now and finally got around to doing the SEGR.

gmctd · **Posted:** Sat Aug 02, 2008 10:12 pm

Good - now we can go from wild-a**ed-guessing to semi-educated guessing - 1140 indicates problem with the vacuum circuit, which supplies wg solenoid - check the connector and vacuum lines on the unit right behind the airbox next to the TCM - P0101 is the expected MAF error - P0102 doesn't register in the KJ CRD heirarchy, but is right down there in the MAF DTC area

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Thanks for the reply. So, if I do not have the P0101 error with my SEGR, can I assume it is working?

Also, what is a TCM? You mentioned it in your post and said to check stuff next to it. Thanks!

gmctd · **Posted:** Sat Aug 02, 2008 11:44 pm

Transmission Control Module, there on the passenger-side front fender between the airbox and the coolant reservoir - that gizmo-lookin' thing is the ECM-controlled vacuum modulator\reservoir - DTC P1140 is all about that thing - clear that up as it affects Boost - SEGR must be ok if no P0101.

geordi · **Posted:** Sun Aug 03, 2008 9:27 am

Since we are doing code scanning on this rainy morning...

Last time I scanned mine, I had 3, but I think one was a glitch code:

P0731
P0876
P0000

I'm pretty sure the last one is just the computer being annoyed about something, but it's not sure what. The other two keep reappearing however.

gmctd · **Posted:** Sun Aug 03, 2008 10:57 am

None of those show as valid for the KJ, Geordi - using the SGII?

geordi · **Posted:** Sun Aug 03, 2008 3:20 pm

Yea, I was. I guess I should pull out the AutoEnginuity and see if there are any new updates for the program yet.

I must say, I was fairly disappointed in that thing - It looks at lots of stuff in the modules, but its all look-but-dont-touch. Not cool.

gmctd · **Posted:** Sun Aug 03, 2008 6:15 pm

Yeah, I'll have to take the hit for that - I could see the required points but didn't have access to the KJ to fully test things out, so my bad - however, AE is still the best OBDII\CAN scantool out there below 3kbucks, avg eBay price for a DRBIII - AE does have a few free upgrades onsite to v6.1 - ennyhoo, run it by AE, see what transpires

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

Ok, I don't think its my SEGR. Wife and I rechecked every pin and wire connection. Everything is as it should be.

The only thing I noticed out of ordinary is that the T41 has continuity with pin 9 (very little resistance) and also has continuity (3.4 ohms) with pin 6 which is the ground pin. Is this normal? This was checked with battery disconntected and vehicle in park gear.

I cleaned the MAF and eliminated P0102.

All I'm left with is P1140 which I'll troubleshoot next month when I get my first day off from work.

CATCRD · **Posted:** Sun Aug 03, 2008 9:36 pm

Drewd wrote:

Ok, I don't think its my SEGR. Wife and I rechecked every pin and wire connection. Everything is as it should be.

The only thing I noticed out of ordinary is that the T41 has continuity with pin 9 (very little resistance) and also has continuity (3.4 ohms) with pin 6 which is the ground pin. Is this normal? This was checked with battery disconntected and vehicle in park gear.

I cleaned the MAF and eliminated P0102.

All I'm left with is P1140 which I'll troubleshoot next month when I get my first day off from work.

P0102 is the classic code you get when unplugging the MAF.

All signs (except the error-filled FSM) point to P1140 being the FCV. Case in point, my FCV is locked in the open position, and I have this code. Also oldnavy's experience here:

Quote:

Yep that is the one D/C said to replace as it is a code # for older gasser throttle body valve that hasn't been changed over in the system. They replaced the Flow Control Valve and no more CEL. The tech even tested it by unplugging the old one on the engine and plugging inthe new one and then clear the CEL and it didn't come back on. When he plugged it back into the old FC Valve it threw a code so he new he had the problem cured. Now the young tech that worked on our CRD is a real diesel tech and does most of the diesel work at dealership and knows of the oil problems with the CCV diesels which includes MB which he is certified on, not to mention Cummins. This dealership has all the Dodge & Sprinter business in about a 150 mile radius, with some coming from big city dealers where diesel is not spoken except by sales staff.

It will do no good to clean until you vent it to air of install a filter of some type. I will be testing a new filter this weekend that filt under engine cover and requires no extra plumbing required and less then 5 minute install.

gmctd · **Posted:** Sun Aug 03, 2008 9:46 pm

T41 is tied directly to pin 9 so should measure 0ohms - it is the control end of the AFC relay coil, other end of which is tied to +12v, therefore should measure ground in Neutral and Park, doesn't matter if battery is connected or not - again, if SEGR was not working, you'd be getting various DTC's associated with MAF and EGR - note any odd behaviour with Boost and power which may be due to that P1140

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

CAT,
Thanks for the tip. I don't even know where this FCV (flow control valve) is located. Is it an easy to remove and replace? Is there some way that I can clean or repair it myself? Any tips would be appreciated. If its called an FCV, I'll do a search in the FSM and see if it can be repaired.

Sir Sam · **Posted:** Sun Aug 03, 2008 11:52 pm

Drewd wrote:

CAT,
Thanks for the tip. I don't even know where this FCV (flow control valve) is located. Is it an easy to remove and replace? Is there some way that I can clean or repair it myself? Any tips would be appreciated. If its called an FCV, I'll do a search in the FSM and see if it can be repaired.

The FCV (flow control valve) is located on the intake where a throttle body would be on a gasser. It cannot be repaired and only can be replaced. if it fails in the open position leave it alone unless you have a warrantee. It is a "creature comfort" engine part only that the 2002-2004s KJs did not have.

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

I can't leave it alone. The lil' lady wants that pesky MIL light gone. I'm

that the SEGR didn't do the trick but can confirm it is working as designed.

geordi · **Posted:** Mon Aug 04, 2008 11:56 am

Sir Sam wrote:

Drewd wrote:

CAT,
Thanks for the tip. I don't even know where this FCV (flow control valve) is located. Is it an easy to remove and replace? Is there some way that I can clean or repair it myself? Any tips would be appreciated. If its called an FCV, I'll do a search in the FSM and see if it can be repaired.

The FCV (flow control valve) is located on the intake where a throttle body would be on a gasser. It cannot be repaired and only can be replaced. if it fails in the open position leave it alone unless you have a warrantee. It is a "creature comfort" engine part only that the 2002-2004s KJs did not have.

Out of curiosity, is this the same thing as the intake butterfly valve on the TDI? That was called an "anti-shudder" valve, and only slammed closed when you turned the key off. It was supposed to soften the engine shutdown, but I never noticed my engine doing anything different after I installed the racepipe that eliminated both that and the EGR.

Is there any way of fooling the computer that it still exists? What is the ECU measuring? An airflow change from the MAF (difficult to fool) or just a resistance change from the FCV activation? (easier to fake)

CATCRD · **Posted:** Mon Aug 04, 2008 7:04 pm

geordi wrote:

Sir Sam wrote:

Drewd wrote:

CAT,
Thanks for the tip. I don't even know where this FCV (flow control valve) is located. Is it an easy to remove and replace? Is there some way that I can clean or repair it myself? Any tips would be appreciated. If its called an FCV, I'll do a search in the FSM and see if it can be repaired.

The FCV (flow control valve) is located on the intake where a throttle body would be on a gasser. It cannot be repaired and only can be replaced. if it fails in the open position leave it alone unless you have a warrantee. It is a "creature comfort" engine part only that the 2002-2004s KJs did not have.

Out of curiosity, is this the same thing as the intake butterfly valve on the TDI? That was called an "anti-shudder" valve, and only slammed closed when you turned the key off. It was supposed to soften the engine shutdown, but I never noticed my engine doing anything different after I installed the racepipe that eliminated both that and the EGR.

Is there any way of fooling the computer that it still exists? What is the ECU measuring? An airflow change from the MAF (difficult to fool) or just a resistance change from the FCV activation? (easier to fake)

Yes it is also used as an anti-shudder valve. I notice the difference now that mine is locked open.

As to fooling the computer, Tubo Tim would be your best resource on what the ECU is looking for out of it, but I think the answer is "both".

Turbo Tim · **Posted:** Mon Aug 04, 2008 8:05 pm

The answer is yes. Just unplug the AFC valve. The SEGR is already fooling the ECU.
If you really want to be complete, also disconnect the wire to the relay circuit.
By doing this you may notice more of a shudder on shut down.

Drewd · **Joined:** Mon Feb 06, 2006 12:24 pm **Posts:** 902

If I unplug my AFC valve, will my MIL go away or reset? Right now, it won't even reset with my scanner.

Unplugging MAF Question

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