CEL after intake install

B6/7 S4/RS4
#1

I recently installed a JHM intake manifold and after about 150 miles the CEL came on. I scanned it with my shop’s generic scan tool and got a P1602/005634 - Power Supply B+ Terminal 30: Voltage too Low and P1128/004392 - Fuel Trim; Bank 1 (Mult): System too Lean - Intermittent. I figured it might have been from having the battery disconnected so I cleared it. 150 miles later the P1128 is back. Now it looks like there actually might be a problem so looked I into it with VCDS and here’s what I got.

 Address 01: Engine       Labels: 079-910-560-BBK.lbl

Control Module Part Number: 8E2 910 560 C HW: 8E2 907 560
Component and/or Version: 4.7L LC/93+JHM G 0010
Software Coding: 0007711
Work Shop Code: WSC 06325 000 00000
VCID: 275706F2964ABF2040F
1 Fault Found:

004392 - Fuel Trim; Bank 1 (Mult)
P1128 - 001 - System too Lean - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 126854 km
Time Indication: 0

         Freeze Frame:
                RPM: 1854 /min
                Load: 9.4 %
                Speed: 48.0 km/h
                Temperature: 60.0°C
                Temperature: 0.0°C
                Absolute Pres.: 990.0 mbar
                Voltage: 13.716 V

Readiness: 0000 0101

I did a little research and it looks like I should try re-seating the intake and re-torquing the bolts. Has anyone else run into this and if so what was your fix?

#2

Sounds a bit like a vacuum leak. I think the suggestion you listed is smart. Re-seat and re-torque. Do you hear any type of whistle under acceleration?

#3

None that I can hear while driving or with the hood open at idle. I’ll see if I can hear anything with someone revving it tomorrow. The only thing I did notice just now is when I lightly hold my foot on the gas up to about 1500-2000rpm the rpms drop some once it levels off even though my foot has stayed in the same position on the accelerator.

#4

I think this was common on stock cars even. The Intake manifold would back out. Re torque them in the very specific pattern and clear and see.

Fault Priority 0…what does that mean…unknown priority?

#5

Jim,

Chances are very good its a vac leak. This is very common after the swapping of the intake manifold or installation of intake spacers. This isn’t something you’re going to be able to hear. One trick is to get starter fluid and spray it around the base of the intake, where it meets the heads. If you spray the starter fluid in an area where there is a vac leak the RPMs should fluctuate.

Bank 1 is the passenger side. So I would get starter fluid and go hunting on that side. Also go back and check the bolts holding the intake to the heads. They tend to back out after a few hot runs with quick cool downs.

#6

Thanks for the advice CV. This would make a lot of sense. I’ve had quite a heavy foot since the install and really flogged the hell outta the car in the last couple snow storms over the last two weekends. I think if I lived up north I would definitely get into ice racing.

Yes. “Undefined by manufacturer” to be exact.
http://www.ross-tech.com/vcds/tour/dtc_screen.html
All-Data didn’t even have any info on this code when I sent in a request today. Makes me feel less guilty that they have forgot to bill my shop for the last two years :stuck_out_tongue:

#7

-Update-

I checked for vac leaks using starting fluid around the intake. Found nothing. Checked all hoses and everything looked fine. I drove the car for one day with the CEL on. Wednesday morning when I started her up the CEL was off. Rescanned with the CEL off and the same code was there with fault frequency still at 1 and the same freeze frame info. Cleared it and have driven for two days with no codes or CEL. Kinda strange.