I have a 1998 Mercedes ML320 and the steering wheel is acting as an on/off switch for the engine. It started that when I turned left the engine would hesitate, and grew into now turning the steering wheel either direction will completely stall the engine. I’ve replaced the crank case hoses, fuel pump, serpentine belt with tensioner, and lateral acceleration sensor with no changes in this issue. The power steering fluid is full and clean, and the pump does not make any noise. The power steering system does not have a sensor/switch that I can find. Every time it stalls it starts back up without issue unless the wheel is turned, then it hesitates, sputters and stalls. The car has had issues with the ignition switch in the past (previous owner replaced it twice, in 2001 and 2006). There are no stored or pending codes and no lights on. Any ideas on what could be causing this?
The problem is most likely with the steering wheel angle sensor.
This sensor informs the computer how fast the steering wheel is being turned and at what vehicle speed.
The computer then bumps the engine idle up to compensate for the load the power steering pump imposes on the engine to prevent the engine from stalling.
Tester
The steering sensor should trigger a fault code. But it was determined by both an MB dealership and an independent shop to not be at fault (how they came to the conclusion, I’m not sure). Sorry, I should have gone into more detail but I didn’t want to write an essay! That’s how I arrived at the lateral acceleration sensor, through discussion with both of those shops.
They probably had a scanner hooked up, while they turned the steering wheel. Presumably, they saw the steering angle change on the scanner’s screen, while they were turning the steering wheel