When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I’m having a communication error on the OBD2 port with HPT. It has power and the car is in limp mode. I’ve tried checking the DLC on the cluster and it’s giving me no communication for all systems. I have checked all grounds and checked the connections in the doors (I’ve had that issue already). I put a new battery in the car last night, friday I noticed it was these issues. I had the battery out while doing some work there, and when I reconnected I was unaware of the bad battery the car made a really fast clicking noise, I was able to pin point it was coming from near the BCM but not sure what it was exactly.
First make sure your HPT can comm with another vehicle and that it's not your tool !!...If you are still having all "no comms" with all of the modules and can't communicate there are issues with your serial data line !!... try removing each "Star Connector" buss bar or comb as we call it (it looks like a comb) located by the BCM..there are 2 Star Connectors...see if you can once again communicate with the modules...you can start there...BTW when you remove the Star Connector with the 9 wires (#1) I believe the car won't start so just try with key on !!...hope this video helps...starts at 55:50 !!
Check if you have 12 V on pin 16 . If not check MiniFuse 29.
As C5 Diag mention you will have a no start condition if you remove the Star Connector with 10 wires connected. The PCM & the BCM must communicate to get the car started .
First make sure your HPT can comm with another vehicle and that it's not your tool !!...If you are still having all "no comms" with all of the modules and can't communicate there are issues with your serial data line !!... try removing each "Star Connector" buss bar or comb as we call it (it looks like a comb) located by the BCM..there are 2 Star Connectors...see if you can once again communicate with the modules...you can start there...BTW when you remove the Star Connector with the 9 wires (#1) I believe the car won't start so just try with key on !!...hope this video helps...starts at 55:50 !!
checked the star connector yesterday, still no communication
i have power at the obd2, and after finding a ground wire that wasn’t connected I now can communicate with a scanner. But I don’t have any codes to give me clues as to what the issue is.
Check if you have 12 V on pin 16 . If not check MiniFuse 29.
As C5 Diag mention you will have a no start condition if you remove the Star Connector with 10 wires connected. The PCM & the BCM must communicate to get the car started .
car starts runs perfectly fine, I drove it through my neighborhood.
checked the star connector yesterday, still no communication
i have power at the obd2, and after finding a ground wire that wasn’t connected I now can communicate with a scanner. But I don’t have any codes to give me clues as to what the issue is.
every fuse and relay is good.
starting to think the BCM is fried
what ground wire was it ??...so you CAN communicate with ALL the modules now ??...I’m not familiar with HPT so I don’t know it’s capabilities...first thing is you have make sure you can communicate and then you can go from there...so the only concern you have now is a reduced power mode ??...why do you think the BCM is fried ??...codes are not going to tell you what’s wrong..it will guide you in a certain direction...you have to let your scan tool help
I’m showing no codes for everything, and I’d assume if that’s the case something is burned in the BCM but I could be wrong. HPT will scan all modules and clear codes, but you can’t do tests like a tech ii.
i don’t understand why it’s still in limp mode, makes no sense.
I have HP tuner myself .The HP Tuner software of mine ( VCM editor og VCM Scanner) is only communicating with the PCM so you should try another scanner to verify the communication link with and see if you can communicate the PCM or with any other modules on the serial databus .
As far as I know HP Tuner will only display DTC's available within the PCM configuration . No codes from the BCM or any other modules will be shown in HP tuner software .
My guess is that your limp mode is caused by problems in the TAC loop (APP sensor,TAC module or Throttle positionsensor /motor) .
I’m showing no codes for everything, and I’d assume if that’s the case something is burned in the BCM but I could be wrong. HPT will scan all modules and clear codes, but you can’t do tests like a tech ii.
i don’t understand why it’s still in limp mode, makes no sense.
Have you tried using the dic again to check for codes? If it is in limp mode then you have codes set. A bad 02 sensor will not put the car in limp mode.
Have you tried using the dic again to check for codes? If it is in limp mode then you have codes set. A bad 02 sensor will not put the car in limp mode.
yes I’ve tried the DLC again, still nothing. Yea the O2 was bad before, I knew it wasn’t that. It’s a communication issue. The dash is reading 0 on oil pressure and temp gauge is maxed out. So it’s going into limp mode to save itself. But the oil pressure and engine temps are normal on HPT. So something somewhere isn’t communicating with the BCM correctly. And the car runs perfectly fine.
checked the star connector yesterday, still no communication
i have power at the obd2, and after finding a ground wire that wasn’t connected I now can communicate with a scanner. But I don’t have any codes to give me clues as to what the issue is.
every fuse and relay is good.
starting to think the BCM is fried
Where do the OBD wires end up? My scanner works fine in other cars, but doesn't connect to my '03 C5Z. I can see my OBD unit has power (lights flash) but it just won't connect.
Where do the OBD wires end up? My scanner works fine in other cars, but doesn't connect to my '03 C5Z. I can see my OBD unit has power (lights flash) but it just won't connect.
I don't have a pic of the DLC but pin 2 is the data line (the purple wire at each Star Connector), pins 4 and 5 are chassis and signal ground and pin 16 is 12 volt power...I thought you said you were able to connect since you fixed that ground wire ????...you really need a scan tool that can communicate with ALL of the modules to see which one is not on line to effectively diagnose this...if you know how to use an ohmmeter you can disconnect the battery and see if you have continuity between pin 2 of the DLC and both purple wires at the Star Connector...don't know what else to tell you...there is no magic bullet to fix this !!
I don't have a pic of the DLC but pin 2 is the data line (the purple wire at each Star Connector), pins 4 and 5 are chassis and signal ground and pin 16 is 12 volt power...I thought you said you were able to connect since you fixed that ground wire ????...you really need a scan tool that can communicate with ALL of the modules to see which one is not on line to effectively diagnose this...if you know how to use an ohmmeter you can disconnect the battery and see if you have continuity between pin 2 of the DLC and both purple wires at the Star Connector...don't know what else to tell you...there is no magic bullet to fix this !!
that was someone else that replied, and yes I can connect with it with HPT. I thought I could use it to check the BCM codes but apparently not. I’ll be picking up a regular scanner later today.
that was someone else that replied, and yes I can connect with it with HPT. I thought I could use it to check the BCM codes but apparently not. I’ll be picking up a regular scanner later today.
Yes !!... apparently HPT can't do an all system scan and do make sure your new scan tool has that capability...having enhanced and generic OBD2 is the best and bi directional is even better !!...something like this Autel MX808 is good for the price and it's touchscreen !!
Yes !!... apparently HPT can't do an all system scan and do make sure your new scan tool has that capability...having enhanced and generic OBD2 is the best and bi directional is even better !!...something like this Autel MX808 is good for the price and it's touchscreen !!
Picked up a scan tool and had a few codes, all were history, the only one that was current was a U1096. No communication with cluster. Any idea of where I should look?
I don't know what year your car is , but you can check these Minifuses 19 and 25 and also the check ground G104 for good continuity.
If this does not work you can check the connector on the back of the cluster for properly contact & seated
Oelarse covered it !!...have to check power and grounds at the cluster first before condemning it !!...make sure you have system voltage at the fuses and you have same voltage at the IPC....A13 and A14 !!...best to check ground at B13 and also check that splice pack 208 using an old headlight bulb (making sure that ground circuit can carry the current back to ground)...if you need to know how to load test the ground circuit to check I can let you know...are you doing the troubleshooting yourself ????...oelarse probably has a pic of that splice pack !!...what scan tool did you pick up ????
I don't have a picture of SP208 , Rob , only the G104 .
Found this "The ground for the BCM goes through a SPLICE PACK (SP-208). Its located on the engine compartment fire wall on the main wiring harness behind the battery."
No communication
