P0700 U0073 Gauges go to 0 low fuel/security/cel light come on?!?! [Archive] - Pontiac G6 Forum

: P0700 U0073 Gauges go to 0 low fuel/security/cel light come on?!?!

11-03-2011, 09:52 AM

These are the codes i pull...

Here is the story...

Its seems as if every time the temp changes (summer to winter, or winter to summer) my car starts messing up... what will typically happen is while im driving, the gauges will all go to zero, my check engine light, security light, and low fuel light will come on, along with 3 ding sounds. The odometer reads "error" and my transmition starts to hessitate or switch gears very hard. I found if i bang on the center kick pannel on the passangers side, it will make my gauges come back, and then if i pull over, turn my car off, and wait a second, then start my car again im good to go with only my CEL left on... i thought it was being caused by my remote start, so i uninstalled that, to find it made no difference... if there is any more info i could provide please let me kno, it has happened almost every spring/fall since 08 :-/

11-03-2011, 10:14 AM
could be the BCM as thats located in the kickpanel fuse box on the passengers side...i believe the BCM is responsible for gauge cluster info as well not 100% on that

11-03-2011, 10:16 AM
I think the U0700 is a communication error from the bcm, bad bcm? Bad wire elsewere? Bad connector?

11-03-2011, 12:23 PM
If you have the onstar module this is a possible cause:

Service Information 2006 Pontiac G6 | G6 (VIN Z) Service Manual | Document ID: 2324430

#PIC4677C: No Start No Crank Intermittently / No Communication Over High Speed LAN - keywords connector inop inoperative lamp light loose message on onstar U0121 U0101 U2100 U1040 P0700 P2544 U0073 VCIM warning - (Aug 10, 2009)

Subject: No Start No Crank Intermittently/No communication over High Speed LAN

Models: 2008-2010 Chevrolet Malibu

2006-2010 Pontiac G6

2007-2010 Saturn AURA


This PI was superseded to update model years. Please discard PIC4677B.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

A customer may have a complaint of an intermittent no start, no crank condition, and or SES light on with I/P gauges intermittently inoperative while driving. Any of the following DTCs may be accompanied with this complaint. U0121, U0101, U2100, U104, P0700, P2544, U0073

Before beginning to deep dive into any diagnostics first (If equipped) check the VCIM module (Onstar) connector C3 (Black) to be sure that it has been fully seated. This connector has been increasingly showing up as the root cause for loss of HIGH speed LAN concerns.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a ""do-it-yourselfer"". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

2011 General Motors Corporation. All rights reserved.

11-03-2011, 06:42 PM
No onstar...

11-03-2011, 08:24 PM
I had the exact same thing happen when I had my g5, and there was a part(i dont remember exactly what it was, its been over a year) that was related to our power steering that had a recall on it and apparently those were the symptoms of why it was recalled. I got the part replaced and it never happened again (i only had the car 6 months after it was replaced so idk if it was permanently fixed or not though)

I will find the recall to find out what part it was, maybe our issues are related


11-03-2011, 10:29 PM
That could be pretty tough to sort out as they are three seemingly unrelated codes.

U0073: You definitely have an intermittent communication problem between the BCM & the IPC, likely caused by an intermittent short somewhere on the GMLAN serial data circuits.

P0700: The trany control module is throwing a type A (emissions affecting) DTC & you'd need a scan tool that can read trany codes to find out which one.

P0036: Heated O2 Sensor Heater Control Circuit Bank 1 Sensor 2-The PCM detects that the heater control circuit status is incorrect for more than 2 seconds.

First I'd clear the codes & keep a code reader in the glove box. At the first sign of the MIL check the codes.

Next I'd carefully pull the BCM connectors (there are four) & spray them with dielectric silicone spray & carefully reseat them.

Wish I had a simple answer for you.

11-03-2011, 10:49 PM
Wow thats the best answer ive gotten in the 3 years its happened... could you give me any more info about checking for a short, and cleaning the connections ill try them this weekend... thanks a ton!!

11-04-2011, 12:06 AM
Finding an intermittent short is a job for a pro with the right tools & experience. Even then its damn hard. I think you'll be better off taking it to a dealer for a proper diagnosis. The diagnostic fee is about 100 bucks. If you are going to do that don't clear the codes because they need to see them. Hope you got a fat wallet this month.

Cleaning the BCM connectors is relatively easy but remember a new BCM is several hundred dollars should you break a terminal pin.

Purchasing a GM extended warranty might be a smart move if you can possibly can swing it. Except for that aftermarket remote start which I guarantee you they will tell you to remove before they will work on your car.

Maybe jts08g6 or someone else has the answer that ties these three codes together.

You never said how the car is running during these episodes. Is the driveability affected?

11-04-2011, 10:23 AM
Ill get it into my buddys shop tonight and clean the bcm connections, and let you know what happens... the remote start has already been removed, and the car is drivable untill it has these freak outs... then it still drives but it wont shift and when it does it jerks really bad... so i pull over to prevent causing further issues...

11-04-2011, 01:07 PM
I hope that solves it. But since it is so intermittent, you may not find out for awhile.

You might want to revisit all the wire taps that were made when installing the remote start & make sure they are all covered/insulated.

11-15-2011, 04:44 PM
so what i ended up doing is soldering the connections that were "crimped" back together from removeing the remote start (dont think this was the fix, but a good idea non the less) tapeing a power wire that was lose from the remote start (still don't think that was the fix) and then lastley removed the 2 blue/gray connections to the BCM under the deck (from the passanger side kick pannel) and then blowing them out with canned air, and reconnecting them... then I just played with all the wireing down there to make sure everything looked good and secured. I think the fix was mainly in the connections for the BCM. NOTE******* IF YOU DO THIS, MAKE SURE YOU ARE VERY VERY VARY CAREFULL******** ITS LIKE A 100 PIN CONNECTION, AND VERY VERY VARY EASY TO MESS UP!******* AND NOT CHEAP TO FIX! thanks for EVERYONES HELP!!! much appreciated!

11-15-2011, 07:52 PM
Thanks for reporting the outcome. Hope you've seen the last of it.

03-22-2014, 11:49 AM
3 years later and the exact same thing (minus the o2 sensors error) wth is wrong with my car??? I'm going to try the same thing I did last time 9
cleaning BCM connectors) and I'm also going to reprogram my remote start, but I've had that remote start for over 2 years, and haven't had this issue yet.... i'll follow up if anything changes after I clean the BCM connectors, but if anyone has any other ideas, let me know please.


08-19-2015, 05:52 PM
What became of this? My mom has been having this exact problem for the last year or so, between monkeying around with the dealership here and spending money on diagnosing and a new battery and the ignition recall we are now out of warranty and they don't want to fix it under warranty even though it was already brought in for this issue and not repaired due to them blaming the ignition recall.

Any help or direction would be greatly appreciated.