JoeR Posted December 26, 2015 Share Posted December 26, 2015 I've got an International 4700 with a DT466 in it. It has Pedal Position Sensor and Idle Validation Switch Codes in it that have been running me around a little. While scanning the truck my scanner lost communication. I tried 2 other scanners to make sure my scanner didn't die on me. I've never put a scope on the 6 pin connector in order to diagnose a communication problem, so I'm wondering if what I'm seeing is correct. The connector is populated with 4 pins. 12V, Ground, J1708 Low, J1708 High. The 12V and Ground are fine. J1708 Low cycles 0-5V in a nice square wave, looking like any other com line. J1708 High cycles 5-10V This truck has no ABS or Allison Trans to pollute the signal. It's engine only on that line. Any idea if those J1708 voltages are correct? Joe Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 26, 2015 Share Posted December 26, 2015 Typically when measured with a DVOM 1708 low will be .2 to 1v fluctuating and J1708 high will be 3-4v. Usually when I scope it the waves will add up to 5v combined. If your wave is as wacked as you say I'd check the powers and grounds to the ECM before anything else. Here's a J1708 from a later truck, it should be the same. Year/make/model of truck? They didn't build 4700s in 2003, it might be a 4300 or 4400. I can supply you skis if you need them. PM or post the VIN, or call me. Edit: If it's a 6 pin Deutsch it's not a 2003. If it's a 2003 it would have a 9 pin Deutsch and 1708/1939 busses. 1 Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 26, 2015 Author Share Posted December 26, 2015 Great info. Thanks! VIN is 1HTSCAAP3XH200130 You are correct on Model Year. 10th digit is an X, not a 3. Thankfully I ID'd it into Mitchell by VIN, so I got the correct info even though I didn't know what I was working on. :-) Voltages are definitely in the ranges I posted. I can grab the lab scope captures Monday. When I punch that VIN into my Mitchell it says 4000 Series - 4700. They probably mean 4000 to 4700. I interpreted it to mean 4000 series, 4700 specifically. Sorry for the error. Definitely a 6 pin. Here's the pic I took of it. I am recovering from a separated shoulder surgery, so I'm not good at climbing under dashboards yet. I took the pic to see what pins holes were populated. 1 Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 26, 2015 Author Share Posted December 26, 2015 Here is a pic of the 1st pedal position sensor. Idle Validation Switch definitely has trouble. It would mess up during parking lot maneuvers. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 26, 2015 Share Posted December 26, 2015 It is a '99 4700, in the subject header you have '03 which is what threw me. It will have the CEC (single box) ECM mounted on the top left of the engine. If you need a breakout box I have one, and I probably have a good tester ECM too. I wrote a book on this engine and know it well, attached are schematics. (There are some misprints in the skis, like the 1708/1939 bus voltages are missing, the ECM power relay wiring is reversed, and the IPR return voltage is wrong) Check power and ground getting to the ECM, these have huge pattern failures in this area like the fuse in the battery box, the connector plug near the starter, and vdrop across the ECM power relay. I'd check power at the ECM relay output pin first, then backprobe the ECM plug and check the rest. Pull the ECM plugs out and check for green death. What are you using for a scan tool? Good Luck! Here's some pictures from my book and training program: Remove the dust cap with a #1 Phillips: Check the connector for green death, and use a light smear of dielectric on it going back together: Remove the dust cover: Backprobe the connector: Check voltages: IIRC there are 4 hots and 4 grounds. 12.2 is OK because the key is on and the brake backup motor is running (juice brakes). Click on schematics below: EGED180-2 DTE.pdf EGED185-1 DT466E navpack.pdf 2 Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 26, 2015 Share Posted December 26, 2015 Lots of problems with AP sensors, the part numbers have all been updated and they have an overlay harness because of harness issues. Are you chasing a no-start/no comm, or an IVS code? 1 Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 27, 2015 Author Share Posted December 27, 2015 The truck came in for intermittent unresponsive throttle. It has the typical IVS/TPS Code set. The problems occur during parking lot maneuvers. It has had an overlay harness and several TP sensors. The original and one replacement had bad IVS Signals as seen on the scope. Right now I can see no problem with either signal but the problem still occurs. I was going to stress test the wiring next. You are correct about the wiring diagrams being incorrect. In order to find the correct signals at the PCM I had to do continuity tests to all the pins. The IVS signal on the diagram was actually the TPS. The IVS was the next row down. I forgot the pin #s. The no Communication problem is new. I have scanned the truck multiple times without any troubles. I go home one night and the next AM the scanner says No Comm. I’ve used a Nexiq iQ, a Pro Link Ultra on it. The Ultra can do Bus diagnostics. It says J1708 is present but idle. I scoped it and found the results listed above. I’ll post those scope pics too in case you ever want to use them in a class. I’ll check the power and grounds to the PCM on Monday. If you’re willing to send me a loaner PCM, I would gladly take you up on it. I can even send you a shipping label to make it easy. Thanks so much for the help!! Joe Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 27, 2015 Share Posted December 27, 2015 Has the Baro been swapped out yet? It shares VREF with the AP and can short intermittently, taking the AP with it. Not common, but certainly not unheard of. Also, look at AP V at an idle with a DVOM. When it goes under (IIRC?) about .38v the ECM won't recognize the signal and goes to idle only mode with a DTC. Sometimes all you have to do is drill the AP holes out a tiny amount, and twist the sensor in the (now loose) holes to get a tad bit more idle voltage. If it's a city truck you'll have more trouble than a long haul truck with the AP as it gets slammed back to idle constantly from the driver lifting and it pounds out the "up" stop in the assy. Do you have access to Iknow letters, like IK1200440, 1-27-2010? Also, '97 up have a "data driven dash" which means the gauges are fed off the J1708 bus. There's a chance something in the cluster shorted screwing up your 1708, so if it won't talk and your wave is bonkers unhook that. You're sure it has no ABS? If it's air the ABS will be on the 1708, if it's juice it would probably have Lucas Varity which does have a separate single wire bus (and usually a 9 pin connector). There are a pair of red and blue bus connectors in the dash behind the radio area where all of the 1708 stuff hooks together, I can post up pics if you like. Does it have any aftermarket devices on it like QualComm, maintenance minder, fuel manager, or GPS? Those will ride on the bus and drive you crazy, too, BTDTGTTS. Good Luck! Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 27, 2015 Author Share Posted December 27, 2015 I'll have to check when the closed throttle voltage is now. One of the things I did was to slot the TPS, as you mentioned, in order to get the IVS to switch closer to where you first hit the gas. It was reaching about 25% throttle before it switched (not on the scanner. just eyeballing it). I haven't messed with the Baro sensor, but the 5V reference and TPS signal are perfect when truck messes up. Can I unplug it and drive around? If so, it's free to try. If it was pulling the 5V reference down, it would have to be doing it faster than the lab scope can see. It's doubtful, but anything is possible. Joe Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 27, 2015 Share Posted December 27, 2015 If it was pulling the 5V reference down, it would have to be doing it faster than the lab scope can see. It's doubtful, but anything is possible. Not likely. See my edit above, too. Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 27, 2015 Author Share Posted December 27, 2015 This truck has the hydraulic brake setup on it. Definitely no ABS. There are no sensors, plus it never ID'd one when the scanner functioned on it. The dash works intermittently on it, as is common on these, but that wasn't a recent change. I'll disconnect the dash to see if that changes anything. Thanks AGAIN for the advice. Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 30, 2015 Author Share Posted December 30, 2015 Here are a few screen shots to follow up on this truck. My bet is a bad PCM. I'll get one ordered this week. Here is the first pedal position sensor. the Idle Validation switch is bad. Here is the replacement. The same codes reappeared. We adjusted it so the IVS moved when it was closer to closed throttle. It probably had a bad pedal assembly, but the stop doesn't look worn at all to me. Either way, here is a scope shot of when the codes reappeared. Nothing wrong with the signals that I can see. Here are the J1708 signals on the 6 pin connector. Sorry for not overlaying them. I only had one scope lead with me. These are bad. Note that the second one is too high a voltage. Bruce, this is with the dashboard unplugged. Here is a sister truck to this one. Note that both signals are roughly 0-4V Joe Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted December 31, 2015 Share Posted December 31, 2015 I checked in my junk, I have 3 known good ECMs but not sure what they fit, they are all DT466E from '97-03 IIRC. I can sell you one reasonable, too. Did you check what a new one costs, plus programming? It's huge money IIRC. I'm thinking there's a good chance I have a bolt-in-and-run-it ECM and flashing would be optional. I could send you all three and let you plug them in. Did you check powers and grounds to the ECM? Quote Link to comment Share on other sites More sharing options...
JoeR Posted December 31, 2015 Author Share Posted December 31, 2015 I checked in my junk, I have 3 known good ECMs but not sure what they fit, they are all DT466E from '97-03 IIRC. I can sell you one reasonable, too. Did you check what a new one costs, plus programming? It's huge money IIRC. I'm thinking there's a good chance I have a bolt-in-and-run-it ECM and flashing would be optional. I could send you all three and let you plug them in. Did you check powers and grounds to the ECM? Hi Bruce, Power and grounds are good. I didn't test them, but trust the guy that did. I'll give the shop owner your info in case he wants to take you up on your offer. Joe Quote Link to comment Share on other sites More sharing options...
blown99 Posted February 14, 2016 Share Posted February 14, 2016 A little late to respond, but replace the complete pedal and not just the tps sensor. The pedal has plastic gears that wear and create ivs errors. Quote Link to comment Share on other sites More sharing options...
JoeR Posted February 15, 2016 Author Share Posted February 15, 2016 Thanks for the response. This truck has definitely been a challenge. The PCM corrected the problem with the J1708 signal, but the PPS codes are still giving me a run for the money. I have checked the 12V and Ground connections to the PCM until I got tired of watching it. It has had the overlay harness replaced with a home made version. It does it with the MAP Sensor unplugged, and with a couple of different pedal position sensors. The first pedal position sensor was definitely bad, as you can see on the lab scope, but any time the other codes set there is no problem visible with the circuits. The problem has improved, but is not yet repaired. I admit i haven't tried a new pedal assembly, but I might as well at this point. Joe On edit: I hadn't talked to the shop owner in a few weeks. I talked to him about this and apparently the homemade wiring repair did fix the truck. That's a relief. Quote Link to comment Share on other sites More sharing options...
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