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ACERT flash code 93

53K views 9 replies 4 participants last post by  Old Man Emu 
#1 ·
My 04 C15 is intermittantly showing code 93. According to the book this is #5,6 intake valve actuator fault. This first happened over 2 years ago. I had a shop in Sacramento check it out and they found no problems anywhere. When they restarted the truck, the check engine light went out and it never came back on(at least for this problem) till about a week ago. I found by reading the codes, and resetting the cruise, the light would go out. this would happen once or at the most twice a day. Yesterday, the light came on showing code 93, but would not go out. I also noticed a 10lb drop in boost. I was running empty, so I could not really tell if I had a performance issue, along with the boost. After shutting the truck off for an hour and restarting it the light never came back on, and the boost returned to normal. However after about 2 hrs, it briefly came on, and the boost dropped off, only to go out after a minute or so. This happened twice more before I got home. Another thing I noticed, was that a code I had for a bad coolant temp sensor 13 disappeared. I replaced the sensor, to correct the problem about 10 days ago. I was under the impression that the ECM stored codes for 30 days after the fault being corrected. My concern is that the OBD may be playing up and giving me false codes.

Any ideas on what to look for mechanically regarding the valve actuator problem, and how excatly does the ACERT work? Or is this a Cat seceret
 
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#2 · (Edited)
Mine did the same only it was for #1 & #2. Mine was just a loose wire under the valve cover. I'd say yours would be the same since they couldn't find any problem before. The boost loss is from the engine derate because of the code. The code would go away on mine because the wire would only "disconnect" for a second, just long enough to throw a code. Restart and it would disappear.

Should be an easy fix, unless it's in an aero truck where you can't even see the rear 1/2 of the engine. (stupid engineers)
 
#3 ·
Thanks for the input. I'm hoping that it is just something like you say. I'm planing on taking the valve covers off this weekend and checking. I've dropped over 20,000 grand into this yellow piece of junk in the past 2 years and am praying it's something simple.
 
#5 ·
I second that thought...I can't even come close to that figure if I add in all the oil changes and performace parts I've put on mine. Did ya have a inframe done? Hope things get better for ya nad just remember there is light at the end of the tunnel when it comes to a ACERT motor...all they need is some TLC and a few mods and those motors will down right pull:woot::woohoo
 
#6 ·
Just thinking I've probably spent a couple hundred dollars on the C15 Acert I've got (other than standard PM). Fuel filter housing cracked around a bolt (of course I replaced it before I read about the upgraded one) and I think about $50.00 on that loose wire. Not bad for over 300k. I wish I could say the same for the A/C system. (thousands spent there):gaah
 
#7 ·
My truck is an 04 379 Pete, stretched to 315" with a 132" DE sleeper. I picked her up with 450,000 mile on the clock. It ran hot from the start, then just before 500,000 rolled over, the water pump shaft broke, Cat claimed it was a regular maintance item andwould not cover it. Cost $1400 to replace. Less than 3 mths later the Cat Reman pump failed, leaving me needing a tow in Yureka CA. I'll give Cat it's due and they replaced the pump FOC, but I still had to pay for the labor. Changing a pump on a C15 is not an easy job. Next came a new cam, 6 sets of rockers, as the case hardening was lifting of the followers and the cam lobes, along with the pre cooler. The pre cooler is a joke to me. Why mix coolant with air intake? Luckily I did not get coolant into my engine, but the intercooler had about 2 gallons in it. A friend of mine with the same engine had his go and it bent 2 rods. His milage was less than 400,000 and Cat would not warrent it. Replacing the cam, rockers and pre clooer was $6500. Next was the fan clutch, $ 500, then the main one. I started to get white smoke at start up. Was using coolant again, but could find no leaks. Oil was clear. Turned out to be coolant leaking into # 2 clyinder. Replaced the injector and cup seals but to no avail. Whilst warming it up, steam started to come out the crank case breather. Dropped the pan and and it was full of coolant. Removed the head, cracks between the inlet valve seats on #1 thru 5. New head required. Damage done to # 1 & 2 cylinders due to water ingression. Could not replace just the liners, but had to put 2 new kits in. The pistons, and rods were fine, but Cat does not sell just a liner. Whilst reassembling, the threads on the block pulled while final touque on the head. Can't hold Cat responsible for that one, but had to remove head, # 1 liner and heli coil the block. Cat dealer wanted to replace the block, but i put my foot down and had them heli coil it. Total cost for that one was $11600. All with less than 550,000 miles.

I know the truck was used when I bought it, but I did throughly check it out. I'm a diesel mechanic by trade, and short of pulling it all apart everything checked out. According to the download I had done before I bought it, it had no overspeeds but did have one over heat.

Since I've had all this done, the engine has run fine, and has been trouble free. I've kept an eye on the temps, and have not had an over heat. She does tend to run up there though on a good pull in summer, but if it gets to 220 or so i'll drop a gear or so to take the load of it. I feel as if the cooling system is somewhat marginal on the Pete.

I'm not real impressed with the C15. It seams moody. At times it runs quite smoothly, but other times it runs like ****. Shakes and vibrates like hell. Especially around 1300. sounds as if it is mis firing. I put it down to the variable valve timing. Sure would like to find out Cats reasoning and logic behind it. Fuel economy is quite poor. At best I can get 5.2 pulling a box and grossing 80,000 I run at 1200 which is 62mph. Tried lower, but found i need to change down to much. Have gone back to 1300 which gives me the same milage, but also gives me a little more run at a hill. Can leave it in high more. Also found that if I down shift at 1250-1300 and work it up to 1500 it performs a lot better. Letting it drop to 1050-1100 usally means having to drop a gear or more for the same hill. I'm a firm believer in using momentum to get over the rise.
 
#8 ·
Quote: Whilst reassembling, the threads on the block pulled while final touque on the head. Can't hold Cat responsible for that one, but had to remove head, # 1 liner and heli coil the block.

I would put money on assembly error that pulled threads. Most likey put the short bolt in a long bolt spot, I had to repair blocks for a dealer that did it twice in a row!
 
#10 ·
The CAT dealer who done the work claimed that the hole that pulled out was damaged by coolant leaking into the threads. I did not buy it as the damaged hole was the very front and to the side. Quite a way from #2 which was the cyl. giving trouble. But when you are under load, with your engine all torn apart, what can a bloke do. All in all I was happy with the quality of work done . After they road tested it with me, I hooked up and went straight back up. Apart from a sensor problem, which was in fact there before this problem, the engine has ran fine.
 
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