Gauges and TCM issues.
06-26-2019, 01:58 PM
#1
Senior Member
Thread Starter
Join Date: 04-08-2008
Location: Lacombe, LA
Posts: 131
Gauges and TCM issues.
2 weeks ago I had my '08 HHR gauges acting erratic and multiple DIC warning lights as well as hard shifting ( Security, ABS, Brake, Service Traction Control and ESC, Low Fuel, Power Steering) Speedo, Tach and fuel gauge bouncing. I took this as possible low battery failure since the current Diehard Gold was 7 1/2 years old (yet, no starting issues). I replaced the battery and checked codes: U0073,U0101,U0100,P0700,and P2544. I drove it to work the next day and all was good driving in(45 miles temps in the mid 90's). As soon as I left work to go home this all came back. I had to get gas before I got home and when I turned the car back on, and no problems. That is until I drove it again.
I have searched and found where some people take the fuse block apart, and or attach ground wires to the TCM. I have tried the ground wire bit with no luck. I have checked grounds and the BCM under the dash for obvious issues. At the present time, once all codes are cleared, driving for 10-15 minutes will start showing warning lights and then the other issues. Battery voltage is good and 14.6-15 volts while running. Transmission speed sensor on back of trans looks good with no sign of damage. About the past month I would get the Check ESC and Service traction Control in the DIC, and I checked the ABS connectors.
Any and all help would be appreciated.
I have searched and found where some people take the fuse block apart, and or attach ground wires to the TCM. I have tried the ground wire bit with no luck. I have checked grounds and the BCM under the dash for obvious issues. At the present time, once all codes are cleared, driving for 10-15 minutes will start showing warning lights and then the other issues. Battery voltage is good and 14.6-15 volts while running. Transmission speed sensor on back of trans looks good with no sign of damage. About the past month I would get the Check ESC and Service traction Control in the DIC, and I checked the ABS connectors.
Any and all help would be appreciated.
06-26-2019, 02:12 PM
#2
Administrator
Join Date: 10-13-2011
Location: Welland,Ont Canada
Posts: 36,514
Fuse box halves , loose or broken ground wires.
Loose connections at the ECM ,TCM, looking at the external side won’t show moisture or corrosion in the harness connection.
A good dielectric grease should be used.
Disconnect the negative terminal at the battery.
Ground connections can also hide corrosion.
That voltage running shows the alternator is working but what is load test status of the battery? 12.4 volts or lower is a dead battery.
it could be a dead cell or two.
Loose connections at the ECM ,TCM, looking at the external side won’t show moisture or corrosion in the harness connection.
A good dielectric grease should be used.
Disconnect the negative terminal at the battery.
Ground connections can also hide corrosion.
That voltage running shows the alternator is working but what is load test status of the battery? 12.4 volts or lower is a dead battery.
it could be a dead cell or two.
06-26-2019, 03:45 PM
#3
Technical Moderator
Join Date: 01-23-2009
Location: Fredericksburg, Virginia
Posts: 24,696
All of those Uxxxx codes mean loose wire connection somewhere on the CANbus.
P0700 means the TCM has found an unspecified problem.
P2544 means the ECM has told the TCM to reduce torque.
In other words; The Uxxxx codes say there is a problem with some computer, the P0700 says it is the TCM/ECM, specifically a request to reduce the torque output has failed.
So, I would look at the wires and connectors on the TCM and ECM and the transmission. Are the Traction and ESC warnings still there?
P0700 means the TCM has found an unspecified problem.
P2544 means the ECM has told the TCM to reduce torque.
In other words; The Uxxxx codes say there is a problem with some computer, the P0700 says it is the TCM/ECM, specifically a request to reduce the torque output has failed.
So, I would look at the wires and connectors on the TCM and ECM and the transmission. Are the Traction and ESC warnings still there?
06-26-2019, 05:41 PM
#4
Senior Member
Thread Starter
Join Date: 04-08-2008
Location: Lacombe, LA
Posts: 131
The Traction and ESC warnings usually pop up first, Then Brake(sometimes), gauges dropping out, Security, The TPS warning light doesn't stay on even though I have 2 bad sensors. The longest it has gone without a problem was the day after the battery replacement, when I drove 45 miles to work. I have not removed the two connectors on the ECM as I was having a problem removing the connection assurance pins. Have not separated the fuse box as I was concerned something was going to brake. As tight as the fuse box halves were as well as the TCM connections, I think it would be hard to get dirt or moisture in.
06-26-2019, 07:50 PM
#6
Senior Member
Thread Starter
Join Date: 04-08-2008
Location: Lacombe, LA
Posts: 131
I was just thinking that the "new" battery I got from Sam's may have an issue. The car ran fine for an hour drive after the change , and then everything goes crazy within 15 minutes. I'm going tp pull it out and have it load tested.
06-27-2019, 07:33 AM
#8
Join Date: 06-27-2019
Location: AL
Posts: 1
2 weeks ago I had my '08 HHR gauges acting erratic and multiple DIC warning lights as well as hard shifting ( Security, ABS, Brake, Service Traction Control and ESC, Low Fuel, Power Steering) Speedo, Tach and fuel gauge bouncing. I took this as possible low battery failure since the current Diehard Gold was 7 1/2 years old (yet, no starting issues). I replaced the battery and checked codes: U0073,U0101,U0100,P0700,and P2544. I drove it to work the next day and all was good driving in(45 miles temps in the mid 90's). As soon as I left work to go home this all came back. I had to get gas before I got home and when I turned the car back on, and no problems. That is until I drove it again.
I have searched and found where some people take the fuse block apart, and or attach ground wires to the TCM. I have tried the ground wire bit with no luck. I have checked grounds and the BCM under the dash for obvious issues. At the present time, once all codes are cleared, driving for 10-15 minutes will start showing warning lights and then the other issues. Battery voltage is good and 14.6-15 volts while running. Transmission speed sensor on back of trans looks good with no sign of damage. About the past month I would get the Check ESC and Service traction Control in the DIC, and I checked the ABS connectors.
Any and all help would be appreciated.
I have searched and found where some people take the fuse block apart, and or attach ground wires to the TCM. I have tried the ground wire bit with no luck. I have checked grounds and the BCM under the dash for obvious issues. At the present time, once all codes are cleared, driving for 10-15 minutes will start showing warning lights and then the other issues. Battery voltage is good and 14.6-15 volts while running. Transmission speed sensor on back of trans looks good with no sign of damage. About the past month I would get the Check ESC and Service traction Control in the DIC, and I checked the ABS connectors.
Any and all help would be appreciated.
06-28-2019, 10:01 AM
#10
Senior Member
Thread Starter
Join Date: 04-08-2008
Location: Lacombe, LA
Posts: 131
Had battery load tested : 853 CCA , battery is rated for 800@32 degrees F. Voltage while running is 14.6 to 15 volts with High beams on and blower motor on high. Also, when the gauges start acting up the a/c stops getting cold as if the compressor is dropping out. Normally the a/c works great. I think this weekend I will pull the cables off the ECM and check them.