R34 GT-R Hicas Diagnostic

Self Diagnostic Procedure

1. Start the engine

2. Within 10 seconds after turning the key to 'ON', start the engine, turn steering wheel from left to right 20 degrees from neutral 5 times or more times & pump the brakes 5 times. Then press the brake pedal again to enter the test mode.

Diagnostic Item Input

1. Move the vehicle one or two meters at a very low speed

2. Turn the steering wheel more than 20 deg right to left once or more.

Diagnostic Item

11 Control unit

12 Motor power supply

13 Motor output

21 Vehicle sped signal

22 Steering angle signal

23 Steering angle netural signal

24 Rear steering angle main sensor signal

25 Rear steering angle sub-sensor signal

33 Engine speed signal

41 Yaw rate signal

300ZX Procedure

Turbos come standard with High Capacity Actively Controlled Suspension, a fancy way to say 4 wheel steering. There's a visual diagnostic mode to check for problems in the HICAS functions. The 90-93 TTs have hydrolic HICAS running off the power steering pump, where '94+ utilizes electric actuators to handle the rear steering chores. Their codes are a little different, but the procedure is the same. It might required a few tries to make it work. Be persistant!

Procedure:

1. Ignition switch 'off' manual tranny in neutral or A/T in 'P'

2. Start the engine

3. Within 10 seconds after turning the key to 'ON', start the engine, turn steering wheel from left to right 20 degrees from neutral 5 times or more times & pump the brakes 5 times. Then press the brake pedal again to enter the test mode.

4. Turning the steering wheel left or right past 20 degrees from neutral will cause the rear wheels to turn slightly (~1 degree) (1.).

5. Drive the car forward 15 feet under 9mph to enter the full diagnostic mode.

6. The HICAS dash light will flash a code indicating any problems. Long flash is first digit, short flash is 2nd digit.

7. Diagnostic mode is exited when: ignition is turned off, vehicle speed exceeds 9mph, or diagnostic has operated for 5 minutes.

HICAS light codes for '90-'93:

1. HICAS solenoid R.H.
2. HICAS solenoid L.H.
3. Cut-off valve
4. Power Steering solenoid
5. Vehicle Speed sensor
6. Steering angle sensor
7. Steering Neutral positon sensor
8. A/T: Parking Brake Sensor M/T: Clutch sensor
9. A/T: Inhibitor sensor M/T: Neutral sensor

HICAS light codes for '94-'99:

11. HICAS control unit
12. HICAS motor power supply not present
13. HICAS motor output not present
21. Vehicle speed signal not present
22. Steering angle sensor angle signal not present
23. Steering angle sensor neutral not present
24. Rear main sensor input not present
25. Rear sub sensor input not present
31. Parking brake sensor input not present
32. Inhibitor switch (A/T) or nuetral switch (M/T) input not present
33. Engine speed signal not present