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Tahoe & SuburbanThe power, space, and brutal towing ability make the Tahoe and its longer sibling, the Suburban, arguably the best full size SUV's on the market today.
I haven't had a chance to look through the schematics yet. But did find the troubleshooting guide for a dual tank system.
This is from the GM manual for a 2004 Suburban
The analog signals from the fuel tank are routed to the PCM. Which computes a value and sends a Class 2 serial signal to the Instrument Panel Cluster.
According to the GM Manual "The PCM defaults to empty if: it detects a fault in the fuel level sensor ckt OR a loss of Class 2 communications with the Cluster"
All cluster gauges are driven from the same Class 2 signal on pin A6 of cluster; so if other gauges are working that should rule out the PCM's 2nd error condition.
Starting with everything assembled, I'd suggest to unplug both 4pin connectors at both fuel pumps. Place a 200 Ohm resistor (any size within spec) between connector pins B & C of the Primary pump harness. Another resistor between pins B & C of the secondary harness. This should isolate the issue to either the fuel level sending units or chassis wiring/PCM. I'd suspect wiring issues most likely before a bad PCM.
Attached is more info, again from the 2004 manual.
I'm seeing the C152 pin J is the reference signal; with pin K the primary; Pin H the secondary.
With C152 unplugged; the same resistors as above could go between J to K; and J to H respectively on the harness toward to PCM;
Hope this helps, sorry if it's redundant.
Thanks for the reply, i dont have a manual for this but i did find a wiring diagram for my 2001, and i solved my problem,
Thank you sincerely for the help, its crazy how much simple information can resolve a problem, getting the correct wiring diagram yesterday i found the problem, dropped the rear tank today and fixed it.
the auxiliary pump came with a new plug, the instructions for installing that plug were followed, having read them again and then using a wiring diagram i found two colors were wrong, then i went online and found this pump fit a bunch of things and its probly a generic set of wiring colors. once i had the wiring diagram i went in through c152 bulkhead and found green and orange had been switched,
several hours trouble shooting, funny part was the wire switch made the scanner see the rear pump and it seemed like it should be working, it had the correct ref and volts, but the ohm meter at the c152 plug showed me those two wires had been crossed. swtiched them now its all good, was an Airtex pump,
Airtex pump, they are not good no wonder you had issues. I've read too many folks having issues with them among other aftermarket brands.
I know, but AC delco was out in every local parts house,
I found another piece of usefull information for anyone trying to delete the autoride suspension error messages, i will say you need to replace the shocks as once deleted its in default, your driving with no shocks, i am in the process of getting dimensions both compressed and extended so i can put some good regular shocks on it, I think the regular shock for without air ride will work but i have sen others say they wont so i will figure this out on my own, unless you have already been through this and have some insight?
I saw the delete procedure in a forum some where and tried it today, to remove that error message, remove both battery cables, ONCE REMOVED hold them together for about ten minutes remove the RTD fuse, after a good 10 to 15 minutes put the battery cables back on leave the fuse out and tada. no error messages, no autoride, which if you had an error message you knew thhat already this just gets rid of the light and any functions the autoride was doing even when in error mode.
September 13th, 2022, 4:44 AM
