Q45 Stiff Steering And Actsus Error

[reapara]

I am helping a friends Grandpa who loves his 1994 Q45, it has 35k mi and its pretty clean and the engine runs great.

The problem.. its a couple things:

• ActSus light, error code 12, output shaft sensor. Actsus isnt responsive to N-H. But when the ignition is first turned to ON a corner of of the car will drop slightly or lift. If you start the car the Actsus light is off until a certain speed is reached.

• TCS and SLIP light are ON all the time. I cant get the AT to self test with the trip meter + D-3-full throttle.. sequence

• The power steering goes stiff randomly when driving, usually low speed.

• While coasting and slightly on the brake the car does weird slowing surges. Not head jerking but something is engaging brakes or its A/T related

• I havent confirmed but I think its stuck in a gear? Maybe first? How would I verify without a gear display?

• Grandpa says a 15amp fuse (could be 10amp) is blowing sometimes when he goes from R - D. It hasn't happened in my testing. He has a gum wrapper pushing up against the 4th fuse in the driver kick panel

Its sounding like a speed sensor.. so what do you guys think and any tips to get the A/T to self test? What FSM troubleshooting or sensor would you test first.

[Q451990]

to NICO! I don't have a lot of experience with the Active Suspension stuff. How is the fuse labeled that blows sometimes?

[Ryantzer]

I don't have a lot of knowledge about the active suspension but the factory service manual has all sorts of diagnostic procedures that will help you figure out where the problem lies.

[reapara]

Thanks for the welcome. The fuse that is blowing is the HICAS, I forget the acronym exactly but it is steering related. I will dive into the FSM and report back what I find.

[Rogue One]

1994 Q45 Factory Service Manual

[reapara]

I decided to focus on the act sus error for vehicle speed. I tested the Y/G wire coming from the IC. It reads 4.1V car off, 9.5V car ON. Then 0v car running and 10V spikes when driving 2-3mph. The FSM says it should be between 0 and 5v. The test feels subjective. Does anyone know if this signal is a frequency or a linear 0-5v?