Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Hey guys, workin on an 08 chevy topkick/c series ambulance with an lmm. Showed up customer said truck would not go over 45, speedometer doesn't work and check engine light. I pull it in, hook up my Mac scanner and find a u1000, u0101 and u0106. 1 was ECM lost communication to tcm, next was ECM lost communication to glow plug module and the other was stored in the tcm saying lost communication with ECM. I busted out the wiring schematic and found all 3 modules are on the GMLAN line wondering if anyone has ever had this issue, maybe a terminating resistor issue? Or a failed tcm
carwrenching.com/how-to-test-tcm-duramax/
? Gonna start tomorrow with ohming data link wires from each module but if I find nothing wrong with wires what would be the best way to rule out and pinpoint individual modules. Thanks for any help.
Post the wiring diagram? I’ve never worked on one of them. If it’s like every other gm pins 6 and 14 should have 60 ohms of resistance between them. If you have 120 that’s an issue or 0 ohms there shorted together
