Check Engine & VSC Lights - 2007 RX 350 - HELP!!

shelbyman

I recently purchased a 2007 Lexus RX 350 87k, well maintained from a 94 year old. The cars will not pass NYS Inspection due to annoying Check Engine & VSC lights on the dash. I spoke to a couple mechanics as well as researched on the web and here's what I've done thus far.

I've changed the engine & cabin filters, replaced the gas cap and unhooked the battery cable and let the RX 350 sit for 30 minutes. I reconnected the battery cable and after 10 miles for driving the Check Engine & VSC lights came back on.

I've taken the car to two different local garages who performed diagnostics on the care and the 5 codes indicated it may have an issue with an ignition coil but the car idles, runs and drives perfectly smooth like new. The other 4 codes relate to the traction control and ABS that point toward the Steering Angle Sensor potentially being bad.

P0351 - Ign Primary / Secondary modules
C1223 - Fault in ABS System
U0124 - Loss Comm w/Lat Accel Sensor/Module
U0123 - Loss Comm w/Steering Angle Sensor
C2177 - TPMS - Initiation not completed

At this point, I'm not enthusiastic about bringing the car into a Lexus dealer and investing $2-300 to find out what the issue MAY be and I'd rather not continue to replace random parts hoping to address the actual problem, which is why I'm posting here.

Has anyone encountered these issues and have any suggestions?

thecardoc3

The last four codes in your list have nothing to do with the engine controls, even though they are still issues that should be diagnosed and corrected. The P0351 is related to the ignition coils, but it's important to understand exactly what the trouble code means. A trouble code doesn't tell you what part is bad, it tells you what test is failing. The P0351 means that the computer isn't seeing the "IGF" signal coming back to it when it commands the #1 ignition coil to fire the spark plug. The signal is created by the control circuit inside the coil when the current rises high enough that the coil should have created the spark. This easily could be a wiring issue, a connector problem at the #1 coil, or just a failing #1 coil control circuit.

Service information has the technician pin in and monitor the IGF signal with an oscilloscope while monitoring the IGT signal to make sure that the coil was commanded to fire. I'll attach the screenshot of how Toyota wants this tested.

You could try swapping coils between two cylinders to see if the problem moves with the coil.