Q: I have a 2004
Toyota Sienna. It feels like it will put on the brakes when I least
expect it. It is just for a second or two, but what a wake-up! I
took it to the dealer, and they said no codes found. So online we go
to find out, after hours of searching, that it might be the VSC or
that it is most likely steering rack bushings, but I have done the
entire brake system to find this out. Ouch on me! Why hasnít
Toyota recalled the model for such a life threat as this is? Any
ó Lorie H.
A: Wow! Letís see
if we can sort some of this out.
Toyota issued a
Technical Service Bulletin (#BR008-04) in late 2004 indicating an
intermittent VSC (Vehicle Stability Control) activation may occur on
early production Sienna and Highlander vehicles due to a faulty
steering angle sensor. Such a fault should include an illuminated
VSC light and audible warning buzzer turning on at the same time. A
VSC activation may involve power reduction, braking and yaw
about this intermittent event on 2004 Siennas say it can be quite
If your vehicle
identification number precedes 5TDZA2C#4S194312 (check the final six
digits) or 5TDBA2C#4S025440 (final six digits) this is definitely
something to look into. The bulletin indicates a DTC (diagnostic
trouble code) may or may not be present, and sensor replacement with
a revised version is advised.
If your Sienna is a
candidate for the revised sensor, Iíd push hard for this being
performed out-of-warranty due to the obvious safety concern and DTC
being published (contact Toyota directly).The sensor is pricey
(about $400 to $500) plus installation and zero-point calibration (2
or more hours of labor).
If you havenít
noted the VSC light and tone, and thereís no DTC, it still might
be a good idea to have both the steering angle and yaw sensors
scrutinized for brief glitches by a sharp tech using the graphing
mode of a scan tool or lab scope. If they show clean, this should
put any VSC concerns to rest. Your comment regarding the steering
rack bushings puzzles me, as worn-out rubber bushings would result
in steering looseness, wandering and possible instability rather
than being involved in an unexpected braking event.
As with any
intermittent situation, documenting the specific driving conditions,
possible illuminated warning indicators, road surface, temperature
and other factors will help a service technician to best duplicate
your concerns and be able to apply the best diagnostic methods to
narrow down the cause.
Q: My lube shop is
bugging me to do oil changes every 3,000 miles. Hasnít this been
busted as unnecessary? My oil minder usually tells me itís time in
about 6,000 to 8,000 miles.
A: Yikes! The only
circumstance where this may be needed is when a vehicle is operated
in extreme conditions, such as excessive dust, extreme cold,
prolonged idling, demanding workload or (more likely) if run times
donít heat up the engine enough to burn off contaminates from the
oil. If milky deposits are seen at the bottom of the 710 cap (oil
upside down), full warm-ups arenít regularly occurring. Iíd go
with the oil minder recommendation, as most are derived by how the
vehicle is actually being driven.