Dtc p0700 & u0073
 

2006 CHEVY COBALT 2.2 VIN. F WHAT IS U0073 CODE?:clueless:
CODE STORED IN TCM.
CLEAR CODE , RETURNS APX ONE WEEK .
CODE REEDS CONTROL MODULE BUS COMMUNICATION BUS OFF.
DO IHAVE A TCM PROBLEM OR WIER PROBLEM ?

:welcome8: to the forum Jack!

OK, lets try this again without my "stupid' function turned on, you did say U0073 instead of the P0073 my brain saw, thanks for the PM to help jar my "thinking module" into working properly....hate it when it goes goofy. :duh:

From what I've been able to glean from the Cobalt forums and the SAAB forums, this code is usually set by a wiring issue, try re-seating the connector into the ECM after checking if for corrosion. Obviously you need to disconnect the negative battery cable while you're doing this in order to avoid "spiking" the ECM.

Dtc (u0073 )
 

THe DTC is U0073 Control Module Bus Communication Bus Off.

Please see my edited post above Jack, sorry my brain pulled a "Homer" on you.

Welcome Jack, What's wrong with Homer :duh:

Found this - may or may not be relevant:
Service Information
2009 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | Preliminary Information | Document ID: 2470794
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#PIC5350: Intermittent IPC Gauges WOW Multiple warning Lights On May Or May Not Have Codes P0575 U0140 U0121 U0073 P0703 Set - keywords ABS boost cluster communication DTC gage gauge inop inoperative IP light - (May 12, 2010)


Subject: Intermittent IPC Gauges WOW, Multiple Warning Lights On, May Or May Not Have Codes P0575 U0140 U0121 U0073 P0703 Set


Models: 2009 - 2010 Chevrolet Cobalt W/UAF Configurable DIC




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

Condition/Concern:
Some customers may comment that the IPC gauges WOW and/or multiple warning lights are illuminated. Upon inspection technician may find DTC's P0575 U0140 U0121 U0073 P0703 stored.

This may be caused by a pinched harness between the I/P carrier and body mount.

Recommendation/Instructions:
Remove IPC & instrument panel cover to gain access to the configurable DIC harness. Inspect harness 14 inches from display at the IP carrier mount on left side of dash for pinched wiring - See attached photos.








See SI Document ID: 1378906 for approved GMLAN wiring repairs.

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.

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another bit of info:

check the trans wiring harness that is under the beauty cover for the engine (plastic engine cover). Check for a pinched harness at the engine block near the oil filter, for a bare spot. If no problem then check the 20 way connector for proper connection and pin fit, and make sure it is full seated.