Mark T Posted May 7 Share Posted May 7 Corrosion. The copper turns green and looks sorta like Comet Cleanser. You may not get that ailment where you live. It can be tricky to spot at times. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575310 Share on other sites More sharing options...
The Heinz Posted May 7 Share Posted May 7 I'd have to have either the part number or your VIN to see if I have a lead on the harness. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575316 Share on other sites More sharing options...
CmLandWorx Posted May 8 Author Share Posted May 8 On 5/7/2025 at 9:44 AM, The Heinz said: I'd have to have either the part number or your VIN to see if I have a lead on the harness. here are the original and updated part numbers for the wiring harness Original 20844867 New. 21401681 Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575370 Share on other sites More sharing options...
Mackpro Posted May 8 Share Posted May 8 On the CXP and CTP only , Mack can’t seem to get an exhaust temp sensor that will last more than 6 months to a year. Their solution is to delete the sensor and gauge and reprogram the dash cluster to delete it so it won’t derate the engine. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575373 Share on other sites More sharing options...
Mackpro Posted May 8 Share Posted May 8 Back in the day we did this to all the CXP and CTP truck around here. If the sensor shorts out and tells the ECM the exhaust temp is to high it derates the engine. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575376 Share on other sites More sharing options...
The Heinz Posted May 8 Share Posted May 8 1 hour ago, CmLandWorx said: here are the original and updated part numbers for the wiring harness Original 20844867 New. 21401681 That harness very much so is unavailable nationwide. There is a single dealer showing one: Gabrielli Truck in Bloomsbury, NJ; I'd call them and see if you can buy it from them. Other than that, a VOR order using your VIN is your only way to get one. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575378 Share on other sites More sharing options...
Mark T Posted May 8 Share Posted May 8 56 minutes ago, Mackpro said: Back in the day we did this to all the CXP and CTP truck around here. If the sensor shorts out and tells the ECM the exhaust temp is to high it derates the engine. I had good results just getting a new sending unit and zip tying it to something close to the exaust area. Then I stuck a pipe plug in the hole. Of course the gauge doesn't work, but it'll stop it from going through the derate thing. There were other wires close that weren't too hot and I kinda aimed the probe part towards the heat. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575381 Share on other sites More sharing options...
CmLandWorx Posted Tuesday at 06:28 PM Author Share Posted Tuesday at 06:28 PM I was able to get a harness, should be here today. When putting the valve cover back on are there torque specs for the bolts and an order that they should be tightened? Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575636 Share on other sites More sharing options...
Mark T Posted Tuesday at 10:07 PM Share Posted Tuesday at 10:07 PM 3 hours ago, CmLandWorx said: I was able to get a harness, should be here today. When putting the valve cover back on are there torque specs for the bolts and an order that they should be tightened? Valve cover isn't too critical as far as torque. (doesn't it have those bolts with the springs) Just be sure nothing is pinched anywhere and careful with the vent tube. Be nice if the EGR plug doesn't give you issues. ( be careful with it, the heat makes it brittle ) Pretty much, if you took something off, put it back on. Don't be affraid to use your phone for pictures before taking stuff apart. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575660 Share on other sites More sharing options...
Joey Mack Posted Tuesday at 10:46 PM Share Posted Tuesday at 10:46 PM Yes to spring loaded, 25 lbft. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575670 Share on other sites More sharing options...
CmLandWorx Posted Thursday at 08:39 PM Author Share Posted Thursday at 08:39 PM Got the new harness in, truck is still having the same issue of not registering boost pressure. about 5 min into a test drive I did get high exhaust temp warning and the gauge was maxed out. could the pyrometer shorting out cause the intake manifold sensor to not work? Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575784 Share on other sites More sharing options...
Mark T Posted Thursday at 08:52 PM Share Posted Thursday at 08:52 PM 12 minutes ago, CmLandWorx said: Got the new harness in, truck is still having the same issue of not registering boost pressure. about 5 min into a test drive I did get high exhaust temp warning and the gauge was maxed out. could the pyrometer shorting out cause the intake manifold sensor to not work? Could be making it derate. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575786 Share on other sites More sharing options...
CmLandWorx Posted 8 hours ago Author Share Posted 8 hours ago On 5/15/2025 at 4:52 PM, Mark T said: Could be making it derate. Replaced the pyrometer with one from Mack and still no change in derate. Still not registering boost. im guessing my next step is to replace the ecm or send it off to have it rebuilt. Quote Link to comment https://www.bigmacktrucks.com/topic/75490-07-granite-ctp-713-electrical-issue/page/2/#findComment-575973 Share on other sites More sharing options...
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