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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!
I will definitely have to do that. I just checked the speed sensor connections and cleaned them. Wheel bearings are fairly new, I had to replace a passenger side ball joint recently.
Right now I am at the extent of my diagnostic capabilities. Just drove for fifteen minutes and nothing lighting up.
The ABS light was lit, but no codes. I am also going to take a closer look at the sensor wiring and do a resistance check. I will check with one of my co-workers to see if he has an ABS code reader.
I checked the battery voltage and it was 12.5 volts. Checked the battery in my jeep and it was 12.7 volts. Checked the one in my wife's Dodge (2014 model original battery) and it was 12.3.
The Haynes manual state sit should not be lower than 12.6. I will have an ABS code reader available later this week.
Haynes is a bit misleading if they use those words. Fully charged at 75F is about 12.75V. 12 V at 75F is about 80% discharged That varies by ambient temp. (12.6 V at 75F is a 75% charge)
12.45 V at 75F is considered a battery that can be recharged, less than 12.45 V is a bad battery.
The computers and sensors can function with less, however performance degrades rapidly. For instance, many of the sensors operate with a 5V ref; if the supply is not 12.6 v it is difficult for the circuitry to keep exactly 5V for the ref.
Most of the OBD2 tests need between 9V and 16 V to run.
Thanks for the information Don! The temps here have been running from 79-80 degrees in the morning to 97-99 throughout the day. The batteries that I checked are in my Jeep 3mo. old Duralast Gold, HHR 3 week old Duracell Automotive from Sam's Club and my wife's 5 year old Dodge. I did notice that when I checked the CAN Bus voltages on pins 6 and 14 , I got two different readings: 2.65 on pin 6 and 2.36 on pin 14. I am using a High quality Fluke multimeter for these reading.
So far the, the loss communications are not coming back(yet), just the ABS, Traction Control, Brake and ESC.
Voltage on the CAN is not as important as the resistance. There are 120 Ohm terminators on each end of the buss. so if there is no problem the reading should be 60 Ohms. If one of the modules is malfunctioning that would change to 120 Ohms because it is only hitting one terminator.
Resistance check on the CAN bus was 61 ohms between pins 6 and 14 of the OBD2 interface.
Did you check this with the battery in the car disconnected ?
I can't find the Youtube I posted, but I do remember the resistance value of a good circuit is 120 ohms.
Hope this helps.
Sorry Don but from what I saw it was 120 for a good loop.
There are two resistors in the Can Bus loop.
Correct me if I'm wrong.
07-07-2019, 02:21 PM
