VDC OFF and SLIP lights on - using the Nissan Service center diagnostic to determine root cause

Good news and bad news!

GOOD NEWS:

 the reason why the VDC OFF and SLIP ON lights are coming on...are for what i suspected it to be (check out the last article to see a list of possible suspects I tried to eliminate, your case might be something simpler like one of the  brake lights is out... )

BAD NEWS

 being right meant I had to fork over some cash to get the system diagnosedby the Nissan Service center . Here is that tool that the mechanic used. Doesn't look much different from a regular reader, except it could read codes that my OBDII reader couldnt. Whats surprising is that according to Nissan tech manuals, the OBCII should have been able to read the code C1143 (steering angle sensor circuit is open), but for whatever reason, mine failed to find any problems. Anyways heres an image of the tool the guy used:

I wonder whether I should upgrade the software Im using with my OBDII interface cable. Could be that. I'll look into this more later.


RECAP - The SYMPTOMS:

1) Ignition on
2) Turn steering wheel
3) VDC system disengages with a whirring noise
4) the VDC OFF and SLIP ON lights come on simultaneously.

So turns out... it was a STEERING ANGLE SENSOR issue after all. For whatever reason (maybe misfiring, maybe worn out, maybe ... whatever) this sensor is not working, its located (as the name implies) by the steering wheel, and reads when the steering wheel is turned, what rate is the turn, etc. Essentially, this feeds information to the VDC system to control individual wheel braking to bring vehicle under control when wheelspin or slip is detected. Normally the chances of this happening are higher when the road is slippery (rain, ice) and you are applying quick acceleration with a turn (changing lanes high speed, accelerating onto highway off of ramp).

As I mentioned earlier, Ive been driving carefully to avoid these two conditions, but after a while you want to just drive without paying so much attention, so Ive decided to get this fixed.

THE FIX - THE CO$T

I have to get the part ordered from the Service center. Here's a picture of the part number if you want to look up the price and availability for yourself. Thats $ right there.

Then , Ive got to pay for installation labor - which requires some form of steering wheel dismantling. Another bunch of $ there.

Finally, with a new sensor install, I'm going to need a wheel alignment.The service center will charge another bunch of $ there. Looks like i didn't need a wheel alignment after all

SAVING MONEY:

1. Find someone with access to or get yourself access to a Consult III tool, or some software thats not crap for OBDII code reads -  this will help you determine the real problem without forking money over for diagnostic to the service center 
2. See if you can find the sensor part cheaper . I havent figured out how to do this yet
3. Find someone who can do sensor installs cheaper - i may have found someone to help me with this KA CHING
4. Learn to do wheel alignments or find someone who can do this cheaper - its really just a matter of connecting the tool and aligning the wheel straight and reprogramming. How sad is that? Don't need this after all.. at least not for this job.

I'll report back once these upgrades are complete.

VDC OFF and SLIP lights on - Reading the ABS related DTCs from the right control module

This will be updated once I figure out how to read the codes off of the car using my laptop. I am not entirely sure that my OBD II software will work with this particular type of diagnostic code.


Well scratch that idea - looks like I wont be able to pull the ABS/VDC related diagnostic codes using a regular reader. The reason for this is because the codes are stored on the ABS control unit, which is a different control unit than the regular control unit that these OBD 2 softwares usually read. 
An interesting point: But ABS once there are codes stored, they remain there till cleared.

There is however a manual way to get the car to show you the ABS codes. This is off of the internet, so I will hold off on trying it myself, but incase you want to give it a shot:
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When a problem occurs in the ABS, the warning lamp on the instrument panel comes on. To start the selfdiagnostic results mode, ground the self-diagnostic (check) terminal located on Data Link Connector. The location of the malfunction is indicated by the warning lamp flashing.

SELF-DIAGNOSIS PROCEDURE
1. Drive vehicle over 30 km/h (19 MPH) for at least one minute.
2. Turn ignition switch OFF.
3. Ground terminal 9 of Data Link Connector with a suitable harness.
4. Turn ignition switch ON while grounding terminal 9.
Do not depress brake pedal.
5. After 3.0 seconds, the warning lamp starts flashing to indicate
the malfunction code No. (See NOTE.)
6. Verify the location of the malfunction with the malfunction code
chart. Then make the necessary repairs following the diagnostic procedures.
7. After the malfunctions are repaired, erase the malfunction codes
stored in the control unit. See Below
8. Rerun the self-diagnostic results mode to verify that the malfunction
codes have been erased.
9. Disconnect the check terminal from the ground. The self-diagnostic
results mode is now complete.
10. Check warning lamp for deactivation after driving vehicle over 30
km/h (19 MPH) for at least one minute.
11. After making certain that warning lamp does not come on, test
the ABS in a safe area to verify that it functions properly.
NOTE:
The indication terminates after 5 minutes.
However, when the ignition switch is turned from OFF to ON, the
indication starts flashing again.

HOW TO READ SELF-DIAGNOSTIC RESULTS (MALFUNCTION CODES)
1. Determine the code No. by counting the number of times the warning lamp flashes on and off.
2. When several malfunctions occur at one time, up to three code numbers can be stored; the latest malfunction
will be indicated first.
3. The indication begins with the start code 12. After that a maximum of three code numbers appear in the
order of the latest one first. The indication then returns to the start code 12 to repeat (the indication will
stay on for five minutes at most).

HOW TO ERASE SELF-DIAGNOSTIC RESULTS (MALFUNCTION CODES)
1. Disconnect the check terminal from ground (ABS warning lamp
will stay lit).
2. Within 12.5 seconds, ground the check terminal three times.
Each terminal ground must last more than 1 second. The ABS
warning lamp goes out after the erase operation has been completed.
3. Perform self-diagnosis again. Only the start code should appear, no
malfunction codes.

ABS CODES

Code No. Malfunctioning Part Reference Page
12 Self-diagnosis could not detect any malfunctions.
45 Actuator front left outlet solenoid valve
46 Actuator front left inlet solenoid valve
41 Actuator front right outlet solenoid valve
42 Actuator front right inlet solenoid valve
51 Actuator rear right outlet solenoid valve
52 Actuator rear right inlet solenoid valve
55 Actuator rear left outlet solenoid valve
56 Actuator rear left inlet solenoid valve
25 *1 Front left sensor (open-circuit)
26 *1 Front left sensor (short-circuit)
21 *1 Front right sensor (open-circuit)
22 *1 Front right sensor (short-circuit)
31 *1 Rear right sensor (open-circuit)
32 *1 Rear right sensor (short-circuit)
35 *1 Rear left sensor (open-circuit)
36 *1 Rear left sensor (short-circuit)
18 *1 Sensor rotor
61 *3 Actuator motor or motor relay
63 Solenoid valve relay
57 *2 Power supply (Low voltage)
71 Control unit  <--------- $$$$$$$$$$$$$$$$$$$$

Technical bulletin - VDC OFF and SLIP lights come on after ignition

Came across a 2010 bulletin that describes the VDC OFF and SLIP light diagnosis process. This sheds some more light on the process of diagnosing  at the dealership once they use the Consult III and pull the ECU codes:
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Reference: NTB10-145
Date: December 15, 2010
ABS / VDC CAN DIAGNOSIS INFORMATION
APPLIED VEHICLES: All 2005-2011 Nissan vehicles with ABS and/or VDC
SERVICE INFORMATION
When diagnosing a vehicle with an ABS or VDC / SLIP warning light on with DTCs stored in the ABS / VDC actuator control unit, perform DTC diagnosis first.

^

Do not replace the ABS / VDC actuator control unit without being supported by the DTC diagnosis. ^ Do not erase DTCs before performing DTC diagnosis. ^ Always fully diagnose before performing any repairs. When DTC U1000 (CAN COMM CIRCUIT) is the only DTC stored in the ABS / VDC actuator control unit, use the REPAIR FLOW CHART below. This will assist in proper diagnosis results and repairs in addition to using diagnostic information in the Electronic Service Manual (ESM). --------------------------------------------

So, where does that us? Well two things:

1) If its a serious issue, the dealership will want to replace the "VDC actuator control unit".  Average cost - somewhere from $1000 - $2000.

2) if I can get my hands on a coy of the ESM (ELectronic Service Manual) I can double check that the dealership isnt' BS'ing me on the fix (i have had this happen to me before when I had the minor evap leak, that the mechanic gave me a bunch of tests that were designed to punish my wallet. Plus, knowledge never hurts!)