I have a 2009 HHR LS that started with the Service ECS, Service ABS on the dash last year. When this started I could restart the car and it would be fine for a while.
This has started again now, but I can no longer get the messages to stop coming on as soon as I start the car. The brake, ABS and traction control lights are also on.
I purchased a scanner and came up with the C0550 code. I'm thinking because it got gradually worse, it is probably a bad ground.

Agree, disagree, ideas welcome.

Thanks for your help.

Mike

 

Have you replaced an axle hub? Checked the wiring connectors at the abs sensors at the hubs.
then check ground wire connections ensuring it’s clean and tight.
It sounds whimsical, but any rodent chewed areas on the abs harness?

 

No replaced hubs. Rear sensor wiring looks good. Front is difficult to see, I'll have to get a closer look next weekend.

Thank you for your reply Oldblue!

 

First you need to figure out which module is at fault. My guess is it is the EBCM, might be wrong.

Then you need to figure out what is going on with it. Another guess is a loose wire, possibly in the fuse box or the connector

 

Good stuff!

Thanks Don!

 

I bought an Innova 5410 code reader. The code C0550 comes up under EBCM and says ECU fault. I have checked two grounds and they didn't look bad.
Cleaned them up a bit anyway, no results. Because this started intermittently, I am still thinking bad connection or ground. Someone had a directory of
grounds and/or connections somewhere in the forums for this issue. Can someone help redirect me to that?

Thanks again guys!

Determined to fix this thing!!!

 

It’s a sticky in the How to section or simply search grounds.

https://www.chevyhhr.net/forums/how-...cations-56504/

 

In the how-to forum. https://www.chevyhhr.net/forums/how-...al-library-21/
Try disconnecting the ECM inspect the pins for bent, pushed out the back or corroded. Add some dielectric grease. Do the same for the EBCM.
The EBCM and ECM ground at the top of the trans that wire continues to the radiator support.

When the C0550 sets the module that caused it shuts down (ABS, TC and brake lights mean EBCM). If it was anything else the motor would not run.

You probably need to shop for a EBCM.