Rough Idle After Battery Replacement - Toyota C-HR Forum
LinkBack Thread Tools
post #1 of 2 (permalink) Old 06-01-2019, 07:40 PM Thread Starter
Junior Member
Nestor Alexander Nazario's Avatar
Join Date: Jul 2018
Location: Zephyrhills, FL
Posts: 14
Rough Idle After Battery Replacement

Went to start my 2018 Toyota C-HR (45k on the clock) yesterday. Everything lights up fine when the key is turned over to accessory, but when I go to turn the car over it just clicks rapidly. Hmm. Maybe the battery is low for some reason. I put the battery on a charger, and go about my day. A little over 3 hours later I come back to check on the battery, fully charged and in float mode. Hook everything back up, go to start the car, rapid clicking again. Continue to go about my day. Come out and try again, car turns over slowly, but it finally starts. Let it idle for a bit, took it on a 10-15 minute drive, come home, turn the car off, try to turn it over again, nothing.

At this point Iím convinced my battery is shot. I run to the auto parts store, drop $200 on a battery, come home and install. She starts up fine, but then starts idling EXTREMELY rough (around 600rpm), almost like sheís misfiring, and when I try to hit the gas pedal it limits to 1500rpm. At this point Iím at wits end. I let it run for about 10 minutes thinking the computer needed to reset after being unplugged, but nothing changed.

At this point Iím at wits end. I took the new battery back out, and threw it on the charger at around 9pm, reinstalled at 9am this morning. I have oem style fog lights that I installed myself on a separate switch as to not tap the factory wiring harness, so I unplugged those. Checked for any blown fuses. Cleaned the MAF sensor. Same problems. Only thing that is different is that today, there is no check engine light on whereas there was one yesterday.

Iím at a loss here. She starts fine, spins like a top for about 5 seconds, and then takes a massive ****.
Nestor Alexander Nazario is offline  
Sponsored Links
post #2 of 2 (permalink) Old 06-05-2019, 11:45 AM Thread Starter
Junior Member
Nestor Alexander Nazario's Avatar
Join Date: Jul 2018
Location: Zephyrhills, FL
Posts: 14
So, after 2 days at the dealership, I have my C-HR back.

Somehow the wiring harness to the ECM was knocked loose, which caused a valvematic control module malfunction, which essentially caused my valves to get stuck in place. Thankfully they were able to do a hard reset on the module, and everything is back in working order.
Nestor Alexander Nazario is offline  

Quick Reply

Register Now

In order to be able to post messages on the Toyota C-HR Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome