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While city driving, this van’s abs light came on steady. Shortly after the gauge cluster including speedo blinked out and the idiot lights all came on. This intermittently happened for 20 miles or so. The van then began to run poorly and eventually died completely. The only code showing is U1041. Van turns over well but will not start. Any ideas?
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Sounds like a network communitcation issue.
Here is a brief description of the U1041 code:
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the identification number of the module which sent the message for state of health monitoring/node alive messages. A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an identification number is learned by a module, it will monitor for that modules node alive message. Each module on the class 2 serial data circuit is required to send a Node Alive message every 2 seconds . When no message is detected from a learned identification number for 5 seconds , a DTC U1XXX. XXX is equal to the 3 digit identification number of the module. Contol Module ID = BCM
Here is a applicable network communication diagram for ye’ vehicle:
I have identified some items of interest. There appears to be a lot of connections that should be checked. The splice pack would be a good place to start electrical diagnostics; it can affect the EBCM and the PCM which influence your braking and ignition respectively. SP200 should be located under the dash as a 200+ level connection. A good scan tool can specifically query individual modules and test for communication.
I have a feeling that everything tied into that spice pack may be affected, but the only things obviously noticeable to you right now are failures related to the ECBM, PCM and IPC… try testing out some of the other things, like radio, chime, and remote control door locks. I would not recommend testing out the inflatable restraint system.
Your repair might involve changing out that splice pack. Grab one from the junk yard. Please post before & after pics of your repair. 🙂
The problem seems to have been with the body ground cable attached between the engine and the frame. It is located near the front crossmember under the van. It is exposed to all the road salt we put down during the winter. This one rotted almost completely in half. I replaced it and the van started right up with no codes or warning lights.
awesome fix..
and I learned my lesson: I need to start looking at ground distribution first when it comes to simultaneous multiple device failures.
I was going to suggest checking the battery and it’s connections for starters. Well done on finding that ground cable. I’m going to post this hear just for good measure.
http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems
Thanks for keeping us updated and for using the ETCG forum.
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