Just replace cam sensor on cat 3126. I don't have a scanner to remove fault code. How many times do I have to drive it before it will delete itself?
AFAIK Diagnostic Codes have to be reset using Cat ET. I know of no other way to do it.
Will unhooking the battery and holding the cables together for ten seconds or so clear the codes?
No. Cat gets you coming and going. And JMO, the ET subscription rates are a ripoff. I know they have to pay too, But really? They arent much, but I really started to like the self diagnostics in Hyundai loaders for that reason.
Why do you need them cleared? The check engine light isn't on is it?
No. Would like to just make sure new sensor is working ok.
If the check engine light isn't coming on and the engine starts and runs good then the sensors are good. You would need ET to see the actual output of the sensor.
The check engine light never did come on even with the bad sensor. Just had a code 34 when I scanned it with onboard scanner. Truck had no power and hard start at times. Replaced RPM sensor (code 34) starts easy now but not sure if it has the power it should. Thought if I could erase code 34 and it popped back up again I would know I still have problems. Guess I will have to take it to Cat.
So I could be speaking out of school, so if I am just ignore me. If after replacing the cam sensor code 34 is still active then you have not corrected the problem. Just because it showed a cam sensor code does not mean the cam sensor is bad, it means the cam sensor is bad, the circuit to the cam sensor is faulty , or the cam sensor is not in sync with the crank sensor if it has one of those as well. If you want to test this jump the boost sensor to reference voltage and see if the boost code comes active then hook the sensor back up and see if it goes away. Check the continuity between the cam sensor and ECM. However this is not a definitive test even if the continuity checks out. Check the female terminals on the OE plug to ECM that relate to the cam sensor. A loose connection could show continuity but lack the constant contact to accurately deliver the frequency signal from the cam sensor. You will be unable to check the continuity across the connection to the ECM so you must go visual on this one. Low power could be from a derate, fuel problem or high pressure oil leak among others.
As I said I was getting a code 34. Hard to start sometimes, and no power at all. I took it to Cat and they ran a scan on it too ($130)and said the RPM sensor was bad. They said they could not check everything else until this problem was corrected. They wanted $800 to install it plus $231. for parts. I just don't have the money. I took the old sensor off (HUI pump has to come off) One sensor had a open circuit. I purchased a new one from Cat. Checked it with a ohm meter and had a circuit. (I had looked up what ohms it should read) Truck starts easy now but still don't think it has the power it should, compared to a 1998 GMC with a 3116 and a 2002 FL 70 with 3126, I have. Sometimes I don't quite understand what I read but I was reading that if code is not erased, though sensor has been replaced, with the code still in there it can affect engine performance. Is that right?
Cat Codes fall into 3 categories. Active Diagnostic Codes - the fault causing the Code is present. The fault has to be fixed before the Code can be erased (see below). Logged Diagnostic Codes - The fault causing the Code was there once but is no longer there now. Logged Codes can be erased simply by a technician using Cat ET. Logged Events - these are Events that affect the health of the engine, such as low oil pressure or high coolant temperature. The technician can erase them with ET but he needs factory passwords to do it. This is usually done when the engine is overhauled. If your fault has been fixed (replaced sensor) then the Diagnostic Code should change from Active to Logged. Logged Codes will not affect engine performance. However your sensor fault may have caused what's known as an FMI 13 Code. This Active Code means that a system requires calibration, after installing the new sensor in this case. Until the calibration (whatever it is) is performed the Code will not go to Logged. An FMI 13 Code may affect the performance of your engine, but without knowing if it is there or not it's impossible to say for certain.
Don't know anything about the truck engines and their on-board display but in loaders and haul trucks if you use on-board display to view error codes it will show all codes since they were last cleared. However, assuming I recall correctly, if a code is actually "active" the display will have a note in the right side saying SERV CODE that only shows for active codes. Nice thing about ET is it will in most cases give you a total number of times code was set and the last time it was active.
There are so many versions of the 3126 truck engine, what's the Serial Number prefix of yours ..?
ckm6522 2cpxhd4422hbx
So are you saying I should bite the bullet and take it to Cat again rather than have a truck repair shop erase the code? Like I said, I am just comparing the performance of this to a 3116 ln a GMC and a 3126 in a FL70. Here is another thing I just found out (like I said I just got the truck) I see that it has 24" wheels and the door stickers says it should have 22.5 I think that would affect the power some. I looked on the rear end for the gear ratio and they did not stamp it on the tag. I assume I can get the serial # of the truck and call Kenworth and they can tell me. I just wish when I called Cat and was explaining the situation and I had a code 34, which I knew was a RPM sensor, should have told me it would have to be replaced before they could run all the scans. Now I have to have it done again. (I did run a fuel pressure test, 80 lbs)
Not for a moment .......!! You don't have to replace a defective sensor before a full list of codes can be determined. A test with ET will give a list of Codes, and indicate if they are Active or Logged. Logged Codes can be erased immediately, Active Codes have to be fixed first, thus turning them into Logged Codes, at which point they too can be erased. Your "34" Code can actually be one of 4 Codes when the diagnostic tester is hooked up to it, as follows: - 64-02 Secondary Engine Speed loss of signal 64-11 Secondary Engine Speed no pattern 190-02 Primary Engine Speed loss of signal 190-11 Primary Engine Speed no pattern If you take it to the Cat dealer they ought to give you a download of the Logged/Active codes present in the engine control, and remove the Logged ones for you if you request them to. If the truck is supposed to have 22.5" wheels and now it has 24", then unless someone has changed diffs at the same time (or unless they went to low-profile tyres with the 24" wheels) there will be a major performance difference going to the larger wheels. Your engine is a 3126E rated at 210BHP @ 2000 and 605ft.lbs of torque @ 1440RPM. It did bang on those numbers when it was dyno tested at the factory on 29/03/2001.
You are right Nige. I got to looking at the scan report they gave me. It says code 34 64-2 and 64-11 occ 255 first 6609 hrs last 7531. Maybe when I get the right tires on it, it will improve. In looking over my scan sheet report it says "total time (hours)"2400-2499 rpm at 807. hrs 2300-2399 at 683.20 2200-2299 683. hrs. 2100-2199 572 hrs 200-2099 572.45 hrs and drops on down. Total time 7533 hours total distance 299049 miles 35355 gal of fuel burned. Is this a normal reading? Looks like they drove a lot of hours (most) at pretty near max RPM. And the way I read it, they drove it over 1,000 hours with the sensor bad. Yet when I bought the truck they said it ran fine.
If you want "The Book" on your engine electronics system then PM me your e-mail address and confirm your engine Serial Number - I'll gladly e-mail you a copy. Either your engine is a very early one or you are missing a digit after the prefix, it should be 6KMxxxxx, even if the first digit after the "CKM" S/No prefix is a zero. 255 occurrences of any Diagnostic Code is the maximum quantity the ECM can store, although the hour meter reading for the first and last occurrence of the Code will still be correct even if it logs 10,000 occurrences of the Code. So the suspicion is that your engine logged far more occurrences of the Diagnostic Code for the speed sensor. One good thing is that the new sensor does not need any form of calibration, it's a "Plug & Play" jobbie. I would strongly suggest based on what you're saying that you get the memory on your ECM "wiped" of all the Logged diagnostic Codes so you can start afresh, especially since you bought it only recently. Wiping Logged Diagnostic Codes will not erase your engine history of the hours spent at various RPM ranges.