*** 2012 GMC TERRAIN 2.4 liter FLEX Fuel
I am working on a 2012 Terrain 2.4 with 112k miles which hadn't been well taken care of. I took care of the usual problems, changed cam sensors, VVT solenoids and spark plugs, and now the engine runs smoothly, with no rough idle nor any check engine lights. However, the ABS, Stabilitrak lights and the accompanying chime, keep turning on! A few seconds after I start the SUV, these lights come on, but the brakes and power steering are functioning normally. I have a mid-grade scanner that reads the Electronic Brake Control (ABS) and power steering modules showing no codes on the ABS module, but on the Power Steering module there's a persistent U0121 (lost communication with EBCM) code. As soon as I clear it, it comes right back. The wheel sensors are working well, and the EBCM live data stream shows that all 4 of them are consistently reading the same speeds as the speedometer during a road test. System Voltage shows 14 volts, but ABS Motor voltage is 0. According to various sites, this U0121 code can be caused by a bad EBCM ground, a corroded connector by the gas tank or a problem with the CAN wiring. I already cleaned and inspected both the ground cable on passengers side of engine compartment , as well as the connector on the left side of the fuel tank, but the problem persists. The brakes function well, don't pulsate, and the power steering is normal. Before I start dismantling everything and spending hours probing circuits, I was wondering if anyone had a similar issue and how they solved it. Any help would be greatly appreciated.
Topic Author
