Hi everyone,

I recently had a leaking heater core replaced in a 2008 Urbanrunner. After getting it back from the AC shop it had the ABS light and codes listed below. The AC shop won't help, saying they were on before they got the Runner, so they are of no help. Before looking at each individual code, could there be a common issue causing these codes? Say maybe something wasn't plugged back in? Thanks for any advice that you can provide.

The codes:
C1223 - Malfunction in ABS system
U0073 - Control module communication bus off
U0123 - Lost communication with yaw rate sensor
U0124 - Lost communication with lateral acceleration sensor module
U0126 - Lost communication with steering angle sensor module

To replace the heater core they had to remove the entire dash assembly to get at the housing the heater core and the AC evaporator core is in(I would of had them to replace it as well because if it ever starts leaking you'll be paying the same cost again to replace that $100 part!), which means also unplugging a LOT of electrical connectors, if they left the ABS control module unplugged or not connected properly it would trigger ABS codes.

Thanks for the reply! Thats what I'm thinking happened. Where is the ABS control module located in a 2008 4Runner?

I guess it couldn't be the ABS control module because now that my brain is working correctly the ABS control module I believe is mounted on the side of the master cylinder under the hood.

That being said there are several other control modules under the dash on both the driver's and passenger's side that could possibly affect the ABS system and or throw some of the codes you have, if I were you I would take it back to whoever replaced the heater core and have them fix the issue you now have but didn't have before they did the work!!

YOU LIKELY NEED TO ERASE the zpc and then relearn it. did it a while ago, when i had similar codes..disconnecting the battery for days didnt help...nothing did...apart from shorting some connectors on the obd port.. would dig for the procedure later and repost

Find attached FSM references that show location of the Yawrate/Accleration Sensor and the Steering Wheel Angle Sensor. I recently replaced my AC evaporator and had to pull the air box to do so. Had to unplug both of these sensors in the process. @AuSeeker is correct - you need to remove everything down to the firewall to remove the air box and there are maybe 50-60 electrical connections to unplug to do that job. It would be very easy to miss a few or not seat them fully on reassembly. Not rocket science but does require a methodical approach to get them all plugged back in correctly.

Attached Images

	07 T4R - Steering Angle Sensor.pdf (109.9 KB, 116 views)
	07 T4R - Yawrate & Acceleration Rate Sensor Location.pdf (113.6 KB, 111 views)

This is a good reference, too. It shows the general location of all the ABS system components

Attached Images

07 T4R - VSC System Components.pdf (138.3 KB, 92 views)