HarryBiron093 Posted May 7 Share Posted May 7 Good morning, Truck is a 2001 RD 688 with E7 460. Driving down the road the other day at the engine light comes on and stays on. Its a 3-1 code, I replaced the pyrometer as they seem to only last a year anyway. No change same code still on all the time. I got out the service manual last night and followed the procedure. I figured i would find something in the wiring but it all checked out good less than half a volt everywhere that the testing required and continuity where it was supposed to have it. I get to the second to last step and it has me check continuity between the V2 connector and the rest of the plugs on the VECU. IT says if there is continuity then replace the V2 connector. I had continuity from the V2 plug to certain pins on both the V1 and V4 connectors. The plug visibly appears to have no damage at all how could this be my problem ? Light doesn't ever go out its on as soon as the key is on. I did run jumper wires out of the vecu to the pyro as i wasn't quite sold on the fact that it wasn't wiring. Has anyone seen a failed VECU ? Quote Link to comment https://www.bigmacktrucks.com/topic/74132-3-1-code-et-sensor/ Share on other sites More sharing options...
JoeH Posted May 23 Share Posted May 23 On 5/7/2024 at 6:38 AM, HarryBiron093 said: Good morning, Truck is a 2001 RD 688 with E7 460. Driving down the road the other day at the engine light comes on and stays on. Its a 3-1 code, I replaced the pyrometer as they seem to only last a year anyway. No change same code still on all the time. I got out the service manual last night and followed the procedure. I figured i would find something in the wiring but it all checked out good less than half a volt everywhere that the testing required and continuity where it was supposed to have it. I get to the second to last step and it has me check continuity between the V2 connector and the rest of the plugs on the VECU. IT says if there is continuity then replace the V2 connector. I had continuity from the V2 plug to certain pins on both the V1 and V4 connectors. The plug visibly appears to have no damage at all how could this be my problem ? Light doesn't ever go out its on as soon as the key is on. I did run jumper wires out of the vecu to the pyro as i wasn't quite sold on the fact that it wasn't wiring. Has anyone seen a failed VECU ? Sorry for taking so long to respond. RD model windshields/firewalls leak water and ruin the VECU. EECU is waterproof, VECU is not. Quote Link to comment https://www.bigmacktrucks.com/topic/74132-3-1-code-et-sensor/#findComment-552395 Share on other sites More sharing options...
Joey Mack Posted May 24 Share Posted May 24 Was the EECU programmed recently? If you can, check to see if the pyrometer is turned on in the EECU. Quote Link to comment https://www.bigmacktrucks.com/topic/74132-3-1-code-et-sensor/#findComment-552424 Share on other sites More sharing options...
HarryBiron093 Posted May 25 Author Share Posted May 25 Thank you guys ! I got a used VECU from the dealership and plugged it in and my 3-1 code went away but after driving it I realized that it didn’t have the pyro turned on in the vecu so that’s why it wasn’t working 😂. It’s $700 bucks and it’s 20 years old minus well replace it. I just found it strange that the troubleshooting procedure said to replace the plug that’s all. Quote Link to comment https://www.bigmacktrucks.com/topic/74132-3-1-code-et-sensor/#findComment-552501 Share on other sites More sharing options...
Joey Mack Posted May 25 Share Posted May 25 I told you.... Quote Link to comment https://www.bigmacktrucks.com/topic/74132-3-1-code-et-sensor/#findComment-552502 Share on other sites More sharing options...
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