Using the DRB III to Calibrate a New Cam Sensor in the 4.0 Engine (2000-2006)
- Thread starter sab
- Start date
So because this called the entire thing into question for me, I wanted to compare it to a known-good reader.
My micropod2 and my $35 eBay windows 7 laptop arrived late this week I got that set up this morning.
Thinkdiag2:
So the values match. (I ran the DRB3 with engine off so 5.0 is the last stored value, and the thinkdiag2 was wobbling between 4.9 and 5).
So the only issue is that the thinkdiag2 isn't programmed to correctly interpret negatives. I might submit a bug report and maybe they'll fix that in a future version.
Thanks for confirming the readings. My Thinkgiag2 also bounces back and forth by 0.1 on the cam/crank difference, so I assume it’s pretty sensitive (which I consider a good thing).
I forgot to mention that I briefly reported the negative values (coding) issue to the seller on Amazon and sent them a couple of screenshots.
It might be worth reporting it as well so they take it serious.
ohmisterpabbit
New Member
Thanks to this thread, I picked up a thinkdiag and was able to do a PCM relearn and the P0016 I've been fighting with for years seems to be gone. I don't know why that worked when it seemed like nothing else would and I was smacking my head on a metaphorical wall.
I don't have a screenshot from the thinkdiag but I did see that it's set at 65XX.X , but it does say in sync (can't recall the exact numbers, but before the PCM relearn the learned position was 12, and after the learned position is the 65XX.X) my question, since I have been driving it lately, if I wanted to dial things in closer to the positive side of 0, would I need to go thru the whole process of finding tdc again and then wiggling the opda until i am closer to 0, or could I just loosen and wiggle since it already was set close to TDC, and confirmed by my shop, a couple years back.
I don't have a screenshot from the thinkdiag but I did see that it's set at 65XX.X , but it does say in sync (can't recall the exact numbers, but before the PCM relearn the learned position was 12, and after the learned position is the 65XX.X) my question, since I have been driving it lately, if I wanted to dial things in closer to the positive side of 0, would I need to go thru the whole process of finding tdc again and then wiggling the opda until i am closer to 0, or could I just loosen and wiggle since it already was set close to TDC, and confirmed by my shop, a couple years back.
OP
The value that the thinkdiag is reading is its interpretation from the OBD2 datastream. As long as the value is close to zero (I'd definitely want it under 1° in either direction) for both the Cam Crank Difference and the Cam Crank Learned values, you should be good to go. Since the thinkdiag interprets negative incorrectly, and I don't have one to observe, I'll let @freedom_in_4low advise as to whether you should adjust to a positive value. If the value doesn't decrease as the negative value increases, you would need to adjust, I think.
And to adjust, you simply loosen the hold down screw for the OPDA, and while idling the engine, rotate it ever-so-slightly while watching the Cam Crank Difference value, getting it as close to zero as possible. After you adjust it, perform the ReLearn and confirm that Cam Crank Learned has updated, and you're good-to-go.
And to adjust, you simply loosen the hold down screw for the OPDA, and while idling the engine, rotate it ever-so-slightly while watching the Cam Crank Difference value, getting it as close to zero as possible. After you adjust it, perform the ReLearn and confirm that Cam Crank Learned has updated, and you're good-to-go.
6553.5 would be -0.1, 6553.4 would be -0.2, 6552.5 would be -1, and so on. I'm not sure there's any downside to the difference being negative, but it would definitely be easier to keep it positive so you're not having to convert it in your head in real time. If you have it synced as close as you can to 6553.5 and your DTC is gone, I would leave it be.
Last edited:
ohmisterpabbit
New Member
Okay, I'll get the exact values when I'm home from work, I can say that after the relearn the value didn't shift while driving and I've taken it out on the road at varying speeds and rpms ranging from neighborhood to highway driving, and for the first time since 2018 was able to put more than 5 miles on it without the DTC coming back. Fingers crossed it'll stay, because aside from taking the jeep out to get groceries up the road i haven't been able to take it out and about for a long time. If the DTC stays gone for a while I'll finally feel comfortable doing the other various repairs I wanted to do, but that was my big head scratcher until I found this thread and decided to try it out
Edit: I also wanted to address that it did still say the "at start" was out of sync but everything else read "in sync" after relearn
Last edited:
To avoid the value from being negative, I set the difference to 0.6-0.7 degrees (the difference bounced between those values).
I made it a point to stay above 0.5 but less than 0.8 simply because doing so worked for others.
No need to find TDC. Just loosen the clamp down to the OPDA, rotate it to your desired number, then clamp it back down making sure that your difference number is still dialed in when the OPDA is tight.
I then did the manual relearn after dialing in the difference to match the relearn number to the difference number.
Edit: words
Last edited:
ohmisterpabbit
New Member
Awesome, I'll head over to my buddies this week and dial it in a bit more, gonna be replacing the blower motor resistor when I go over there too, since my apartment gets a bit frustrated if people work on cars at the complex, even for stuff that doesn't involve fluids lol
ohmisterpabbit
New Member
Looking at the numbers i definitely need to dial it in a bit, it's synced at 6551.7, and the recently relearned value is 6551.5 so if my math is right that's around -2 and I can definitely improve that. Just gotta find a spot I can pop the hood and do it as my buddy is currently feeling unwell today and we can't get together
OP
I think you're on the right track. I'd try to get it down in the -.5 (6553.1) to +.5 degree range to have the best long-term chance of no codes.
If anyone else has a thinkdiag2 and a separate temp gauge for their 42RLE, I'm curious how your trans temp readings compare.
The TCM data stream function of my thinkdiag2 reads high by about 20* when compared to my aeroforce gauge (reads off the PCM) and my analog Autometer gauge that I hooked up to verify which gauge was correct.
Edit: I let the thinkdiag2 folks know that their trans temp reading is incorrect.
The TCM data stream function of my thinkdiag2 reads high by about 20* when compared to my aeroforce gauge (reads off the PCM) and my analog Autometer gauge that I hooked up to verify which gauge was correct.
Edit: I let the thinkdiag2 folks know that their trans temp reading is incorrect.
Last edited:
OP
Paging all thinkdiag2 owners from this thread:
@richard-jefferson, a new member here, has posted in this thread that he's trying to get a working cam position sensor for his 2003 TJ, and like the rest of us, he's discovering that the OEM sensor is no longer available. I told him that some members have had luck using the thinkdiag2 on their NGC-equipped (2005-2006) TJs, and that it might also work for his JTEC+ PCM. Has anyone been able to connect to a JTEC+ (1999-2004) PCM with a thinkdiag2? We're trying to find out if it can perform the SET SYNC procedure (see my first post in this thread). In the absence of that procedure, perhaps there's a data channel available like the NGC's CAM CRANK DIFFERENCE that could be monitored while rotating the OPDA to sync the cam and crank position sensors. I have neither a thinkdiag2 nor a JTEC+ TJ, so I'm "flying blind" here. Can you help?
Edited to add the graphic of the JTEC+'s SET SYNC procedure from Post #1, for convenience:
@richard-jefferson, a new member here, has posted in this thread that he's trying to get a working cam position sensor for his 2003 TJ, and like the rest of us, he's discovering that the OEM sensor is no longer available. I told him that some members have had luck using the thinkdiag2 on their NGC-equipped (2005-2006) TJs, and that it might also work for his JTEC+ PCM. Has anyone been able to connect to a JTEC+ (1999-2004) PCM with a thinkdiag2? We're trying to find out if it can perform the SET SYNC procedure (see my first post in this thread). In the absence of that procedure, perhaps there's a data channel available like the NGC's CAM CRANK DIFFERENCE that could be monitored while rotating the OPDA to sync the cam and crank position sensors. I have neither a thinkdiag2 nor a JTEC+ TJ, so I'm "flying blind" here. Can you help?
Edited to add the graphic of the JTEC+'s SET SYNC procedure from Post #1, for convenience: