2007 Hino 268 -- Check Engine Light / Limp.... no codes read?

Davenpbl

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Hey everyone,

Having a problem running down the source of my limp mode. I have a 2007 Hino 268 that starts up no problems, no lights. When you go about 500 ft or more, the CEL comes on, and its limited to 35 mph or under...feels like limp mode. I've had it with two mobile mechanics, and the Hino dealership, no one could get a code from the ECU. The dealership can't take me in for a diagnostic until after the new year. Anyone come across something like this before?

We recently changed the ignition because of a stuck pin, but the service center swears it shouldn't have any impact (no transponder keys or reprogramming necessary on an 07).

We changed the batteries out for brand-new as well since the old set had a significant amount of corrosion. Did a quick check of some fuses.....

Any recommendations are appreciated! We'd like to get rolling for the holidays!
 

Davenpbl

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Oh, should also mention, we can start it up and run for as long as we want at a stop. Rev as high as we want... no CEL. Its only after we've moved for a few minutes that it comes on.
 

greasytshirt

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They are right about the ignition and key, there are no security system components.

Super weird problem you have here. Do you have a gps or eld or anything like that wired up?

Water in the firewall junction box can cause havoc. 2007s have bolt on covers, but water can still get in from windshield leaks. Might be worth taking that cover off, opening connectors, and looking for moisture or corrosion.

Your dealer can open a tech assist case for engineering help with this. They are usually helpful.

I'd also check the physical layer of the CAN for correct resistance. Anything funky here can cause communication issues.

Confirming power and ground at the ECU would also be on my to-do list.
 

Davenpbl

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Thanks. I do have a Bluetooth ELD, but we’ve had it disconnected for days while we troubleshoot the codes via the 9 pin port. We’ll check these few items and go with it. Yeah very weird to us, starts up and runs great…until it doesn’t. You’d think the code would set and stay set if it was something mechanical.
 

Hino123

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Sounds like a classic case of a P0045 code for the VGT actuator. There is a linkage rod on the turbocharger that attached to an actuator. The actuator moves the rod when commanded and increases/decreases boost pressure. When you turn the key on, it should move the rod down them up I believe. Have an assistant turn the key on while watching the rod. Make sure it moves. Then I usually attempt to move the rod down with a long bar. If you are not able to move the linkage rod then you will need a turbo. That’s my best guess.
 

greasytshirt

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It should, yes. That's the big mystery here. I would want confirmation that it's set a P0045 before committing to turbo replacement.
 
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Hino123

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You can diagnose a P0045 without a code. If the Linkage rod is binding that is a problem and would explain the symptoms you are describing. That being said. You can not pull engine codes through the 9 pin DLC. That port is for Allison transmission and Wabco brakes. All ECU/engine codes must come from the 16 pin. Hino/Isuzu/UD use a different protocol than other one’s. If you plug a generic 16pin code reader in it most likely will not read it. The fact that you state the CEL comes on and it is de rated when you go over 35 mph says to me that you have a turbo, egr or fuel related issue. Fuel and Egr don’t match the description you have given for this issue…. However a sticking turbo sounds very plausible in this situation. Check the rod or have the codes pulled through the 16 pin. Let us know what you find.
In my experience I have only found 3 things that will cause a derate on 2005-2007 trucks. Turbo 90%, egr 5% and fuel pressure 5%. On the 2008-2020 truck you can pull the codes from the meter/cluster. 05–07’s are harder. I know you also state the dealer pulled codes but found no codes. Are you saying the CEL light was on and they were not able to pull ANY codes from the ECU. ?
 
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Davenpbl

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Dealership said its the Turbo... a few local diesel mechanics weren't able to pull any codes from the ECU, and at one point the dealership couldn't either. Haven't been told why on that yet.

They're building me a quote to repair. Anyone know typical costs?
 

Davenpbl

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Ok the estimate does show a P0045 code. Quote is $4500 to replace. $2.5k for the part and $1.5k for labor. No answer on why it couldn't read codes last month when I brought it in for quick diag....
 

Hino123

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$2200 for a turbo sounds about right. Plus a turbo installation kit. $1500 for labor seems a little steep. That being said door rates have gone up. If you have the turbo installed by the dealer you get a warranty on parts and labor (usually). Good to know you were able to pull the code. Let us know how it turns out I believe warranty time for a turbo is 4hrs. We usually charge 4-6 for a reference.
 
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