turner1950
7/27/2007 1:51:25 PM
My check engine light on my 1997 Miata (53,000 miles) came on and Autozone read Code #1170; can someone confirm this is the front sensor. If so, can a novice mechanic replace this himself?
tomthedog
7/27/2007 8:52:54 PM
from my '96 fac book "P1170: heated O2 sensor (front) (inversion)."
TS is as follows
poss cause: low fuel, O2 sensor bad, bad wirs to/fom O2sensor (term A to ECM term 3C), air intake sys, fuel sys, ign sys malfuntion.
a) poor connection at O2 sensor (corrosion/rust/loose wires)?
b) volts at ECM term 3C: ign on = about 0v, cold idle = 0.1-0.9v, hot idle = <1.0v, hot accel = 0.5-1.0v, hot decel = 0-0.5; OK?
Y = step e
N = next
c) continuity check wire O2 term A to ECM term 3C, OK?
Y = next
N = repair
d) are the following sys OK: fuel injector, press regulator, mass air flow sensor, eng cool temp sensor, plugs, air suction (rich/lean fuel condition)?
Y = replace O2 sensor
N = repair bad sys
e) clear code. code comming back?
Y = replace ECM
N = bad connection/short, find and fix.
as you look at the O2 sensor connection you should have two tabs on top and one on each of the other three sides. read from left to right, top to bottom the term locations are: A,C, B, D. on the ECM, it's alpa+number. each block is a number, the largest is #4 which should be on the left as you look at it. letters are read from top to bottom, right to left.
O2 sensors are pretty easy to change out. just spray ALOT of wd-40 on the sensor the night before, MAKE SURE THE ENG IS COLD TO THE TOUCH, unless you want to burn up you car. hope it helps, good luck.
