the_twig_187 Posted September 13, 2016 Share Posted September 13, 2016 2013 F-250 (6.2L gas) no crank no start... Service advance track light on, wrench light on, TPMS light on, service brakes light on. No communication with the PCM... Code (U0100= BCM lost communication with the PCM) Checked the 2 power inputs to the PCM (both good) Checked the 3 ground inputs to the PCM (all good) Checked the resistance of the MS/CAN network (60 ohms which is within the tolerance spec) Checked both door scuff plate wiring harness and verified no green rot (which would have shown up in the MS/CAN resistance measurement) *just want to verify I'm not missing anything before calling a $800 PCM Quote Link to comment Share on other sites More sharing options...
forddieseldoctor Posted September 13, 2016 Share Posted September 13, 2016 Did you test the power and grounds under load? I got burned by 2 strands left of a wire on a cummins is a sterling last year. Quote Link to comment Share on other sites More sharing options...
the_twig_187 Posted September 13, 2016 Author Share Posted September 13, 2016 Yes... All 3 grounds and both power wires will light a test light. One power is sent from the BCM and the other power is sent from the BJB, all 3 grounds are grounded with bolts to the bulk head right beside the PCM Quote Link to comment Share on other sites More sharing options...
mchan68 Posted September 13, 2016 Share Posted September 13, 2016 What about HS-CAN? Does this vehicle have any aftermarket bullshit installed? What were the exact events that lead up to this? Quote Link to comment Share on other sites More sharing options...
the_twig_187 Posted September 13, 2016 Author Share Posted September 13, 2016 The ppt does not have you check the HS/CAN network...I believe the PCM does not communicate over the HS network Quote Link to comment Share on other sites More sharing options...
8WA Sman Posted September 13, 2016 Share Posted September 13, 2016 Does the CEL come on in bulb check? I am guessing you already looked @ GSB G0000094. According to WSM 418-00 the PCM is on the HS-CAN. Just wondering what the result of PPT QA was? Is there ETC data in any of the other modules? Did you look @ PPT AI in the WSM? Sorry more question then answers... so by default @ this time I do not vote to "Throw" the PCM Quote Link to comment Share on other sites More sharing options...
Matt Saunoras Posted September 14, 2016 Share Posted September 14, 2016 The PCM is most definitely on the HS-CAN network. I would not put a PCM in yet. HS-CAN pin fit issues have been frequently found in C210 and C212 under the dash. Quote Link to comment Share on other sites More sharing options...
YukonTyler Posted September 14, 2016 Share Posted September 14, 2016 Disconnect negative battery and ohm out your HS CAN across the DLC. 60 ohms is what you're after - get that reading and you're correctly seeing both terminating resistors on the network. If you read 120 then (in your circumstance) expect to find either an open HS CAN circuit or a bum PCM. My money is on finding a broken wire. It is almost always a broken wire. Quote Link to comment Share on other sites More sharing options...
cbriggs Posted September 14, 2016 Share Posted September 14, 2016 Is the pcm the only module that doesnt communucate? IE: What are the results of a network test? Quote Link to comment Share on other sites More sharing options...
the_twig_187 Posted September 14, 2016 Author Share Posted September 14, 2016 unfortunately I am no longer at the dealership and am currently working for a private company. My resources are limited but I do have access to a snapon solus scan tool and snapon shop-key online. I do not have access to a IDS or the exact ford WSM. The only modules that seem to not communicate are the PCM and TCM Quote Link to comment Share on other sites More sharing options...
lmorris Posted September 14, 2016 Share Posted September 14, 2016 Gas engines have the TCM as part of the PCM. Quote Link to comment Share on other sites More sharing options...
the_twig_187 Posted September 15, 2016 Author Share Posted September 15, 2016 yes that's why I was at the conclusion that there was something internally wrong with the PCM and it was the cause of the PCM/TCM not communicating. We had to send it to a local dealer as the snapon solus scan tool cannot re-program new modules. Gave the tech a breakdown of my diag and finding and just said to take a quick look and see if I missed anything and if not to go ahead and replace the PCM. Got a phone call from the service advisor saying that he was going to overlay the PCM power wire going from the BCM to the PCM and that it would be ready to pick up sometime today... I was certain that I verified that the PCM wakeup power wiring coming from the BCM to the PCM had power and was able to light a test light when back probing (PCM "B" connector pin 35, VT/OG). But I guess we'll see what happens when I get the phone call from the service advisor later on today Quote Link to comment Share on other sites More sharing options...
the_twig_187 Posted September 16, 2016 Author Share Posted September 16, 2016 So I got the vehicle back from the dealership. The tech said that the ground side of the field coil for the PCM power relay was open and that cuased the no start. This puzzles me because the PCM power relay was the first thing I checked. The PCM grounds the relay and sends power to fuse 33 (VPWR) and fuse 35 (PWR/DIST-BCM). I checked these fuses with the key off (no power on the fuses) and with the key on (power on both sides of the fuses with a test light). I said "ok this proves the relay is functioning correctly" and I moved forward with my diagnosis. very puzzling... Quote Link to comment Share on other sites More sharing options...
tonybullitt Posted September 17, 2016 Share Posted September 17, 2016 Fuses were good so that proved the relay and bcm were good he must have overlayed the wire from bcm to pcm pins 67 and 68 Quote Link to comment Share on other sites More sharing options...
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