Reflash gone wrong...

Jim Warman · March 26, 2009

This all started with a venturi T install... This truck was also up for 08B06 (IIRC).

After the tech flashed the truck, he noticed that one of the 4WD lights was flashing. It was soon determined that the truck needed a gearmotor actuator and one was ordered - too late n the day for next day delivery.

I can't remember what one of the two codes was - the other was P0500. PIDs showed that all of the plates read open at the same time. The customer was mad, undestandably, the light wasn't flashing before and the damned thing had to fail while we had it - he took the truck, anyway.....

and was back the next afternoon with a surge under acceleration and at cruise. 4 codes were in 4X4 module memory - all for the 4WD problem. I soon determined that the surge was because the TCM was commanding a 1 - 3 - 1 - 3 - 1 - 3 shift while accelerating and then a constant 3-5-3-5-3-5-3-5 while cruising at ~50 kph (30ish mph). Remember - no trans codes.

Hotline advised that B59 was crap and I had to download B60 and reflash the whole works.... Finally got the update downloaded and into the IDS, and getting past "there is no later reflash for the...." turned into a circle jerk.

Finally reflashed the PCM... nothing for the TCM (of course - and no apparent way to get there without the chance of worse things going on). Nothing new for the ICM, either.

OK, now it's late, hotline is closed .... it's Miller time....

Next AM, I cleared KAM the hard way (battery disconnect and key on - if that works anymore, I don't know) mand sent an apprentice on a drive looking at OSS and VSS among others. OSS was nice but VSS was a pronounced square wave... Even though the speedo read rock steady, VSS varied by several kph - about 20 or so, IIRC.

The gearmotor had come in with the days freight. The apprentice decided to change it when I had him lift the truck to checked connectors and grounds ... still no trans codes to be had.

Naturally, with the new gearmotor attached, there was no more flashing 4WD light - thankfully, the apprentice decided to go for another drive.... Problem solved.

Two things come to mind.... what would have happened had the decision - yeah, we'll fix that after we cure this shift concern been made?

Second, to me this equates to having to fix your toaster because your TV doesn't work.

Hotline opined that some sort of feedback or RFI had been set up by the gearmotor... While composing this, I realized we hadn't watched the plate PIDs while driving.... I imagine that they might have been toggling between high and low range which might account for the VSS activity..

Food for thought......

Brad Clayton · March 26, 2009

I you make a very good point. In the past I would let known broken stuff ride while trying to fix other problems of more importance. But now with vehicles systems being so interrelated, I go out of my way to fix anything that aint workin right in an effort to get to the root cause of a concern.

2 examples: had a focus that would go into pcm reset mode when you would turn on the accessories. It was just like you cycle the key off and then on while driving. Upon visual inspection noticed that the motor had been replaced by the biggest hack whom I have yet to meet. Bolts missing, lines routed wrong, a/c manifold not even hooked up just dangling, ect. Well after frickin with this thing for a week and even and fse looking at it (who gave up on it by the way), I decided to just put the car back together as it should be. After doing so the car was fixed for it's concern. It turned out that the alternator power wire that is supposed to run over the top of the valve cover was run under the oil pan and zip tied to the crank sensor harness. Talk about some serious rfi.

The other was a 95 powerstroke with a bad pcm (chipped and fried). While getting to that found a few other problems including a seriously screwed up glow plug relay (had a mind of its own). Had a hard time getting the customer to put a pcm in it. Replaced the pcm only and got it running then it stalled then it wouldn't run again. Turns out the glow plug relay was zapping the system such as a bad ebp would with 5 volt ref.

GregKneupper · March 27, 2009

I have a good one here for you all. Customer brings in his 2008 F 250 with a 6.4 for the recall and a missfire. I repair the vehicle by replacing an injector, perform the recalls, change the oil, air, and fuel filters. Road test the truck all is great. The customer picks it up 4 days later. As soon as he leaves he brings it right back and complains that his traction control light is on and will not go off. I pull it back in and sure enough it will not turn off. I run codes and there are no codes in any module. Hmm I think, that sure is strange. So I diagnose the concern and determined the pcm is bad. I ordered one and install it the next day. I flash the pcm and bam, the damn light comes back on. I rediaged it and found the pcm to be bad again. The pcm grounds the light on the switch and it was grounding it for some reason. I contact the hotline and discuss the results of my testing with them. I wait a few minutes on hold and he comes back on and tells me he has figured out the problem. He proceeds to tell me that the truck was not equipped with traction control and was a misbuilt from the factory and by reflashing the pcm I put it back to the way it was supposed to be. This truck has 49000 miles on it I said. He took me through a few things to try to fix it with no luck. In the end I was told to order a new plate for the radio bezel that eliminated the switch. Needless to say, the guy is pissed.