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Problems/Service/RepairsIf you have a problem with your HHR, want a tip on repairing or performing a particular service to you HHR here is the place to post!
Hi guys, new owner of a 08 HHR SS stick shift here.
when I bought it a month ago the previous owner said the battery died once and the key fob stopped working and tpms light came on after.
I tried going to the local lock smith and he said his computer can’t connect to it. I needed a new scanner myself so I bought a Ancel X7 .. I did a bunch of searches only thing I found was the #29 fuse for the cig lighter but mine is fine.
it will connect and check engine codes but doesn’t seem to connect to the bcm or whatever when I go to reprogram the fob with it.
I tried looking for what the pins on the obd port mean but can’t find it. My cars totally stock besides the stereo head unit that I installed with the correct plugs from crutchfield. Everything works. Besides the key fob and tire pressure sensors that is.
the included pic is a random spot I found on the scanner. Is everything showing up? I’m new to diagnostics
Are you a digital computer guru? If not all you need to know is that pin #16 is 12V. The usual reaso that locksmiths can't connect is that they need to erase all of the previously programmed fobs first.
Fuse #29 under hood fuse box powers the DLC and the front aux. power connector.
#29 on the BCM is the power windows.
It is the RCDLR that needs programming for the fob and TPMS.
'08 models need a RCDLR firmware update for the TPM to work after a power outage. That should not affect the remote door locks, unless somebody tried to repair something.
My guess is that "signal ground" is really low ref (0-3 volts but exact) which is "digital" ground, not exactly the same as "analog" ground.
The scantool is powered by the 12V and ground provided by the DLC port, that is also the source for the battery status data.
One in intended to be the return for something using 12V, the other is intended to be used as the ground side of signal wires using much less current. I'm sure it's left over from long ago on OBDI or something, but there is nothing wrong with the designations. Using a power ground for the return on a signal wire can cause a fair amount of noise. Properly the signal ground should go to the ECM and the power ground should go to the battery.
The terminal is either a power or ground it can not be a power ground.
Just a limitation of the English language (and all languages, really.) I think’s a confusing way of saying it’s the ground for the power circuit. The necessity of being succinct leads to ambiguity.
Just a limitation of the English language (and all languages, really.) I think’s a confusing way of saying it’s the ground for the power circuit. The necessity of being succinct leads to ambiguity.
Precisely. Which if that were such we wouldn't be having this conversation.
I guess you could call it signal ground and chassis ground, but there is nothing wrong with power ground, which when sitting next to signal ground, succinctly describes what it does to those who need to know. I certainly know the difference and my products that plug in properly use the chassis, I've seen some that just connect them together and others that use signal ground for power. I don't think it actually matters in an OBDII GM vehicle as there are no signal wires in the OBDII port and I've never tried to follow the wiring diagrams to see if they are actually separate, but consistently ignoring thigs like that when designing compatible products will bite you in the ass one day. When the OBD port was defined, those names were used for a reason. The fact they stopped making sense at some time does not make them wrong. When I was doing instrumentation for coffee roasters, there was definitely a need for a power ground and an analog ground, connected at only one point so that current supplied to the processor and op-amps would not affect the really low level, very high impedance sensor inputs.
08-26-2022, 09:08 PM
