Heater - Honda Acura NSX 1991 Service Manual

Self-diagnosis Check Engine light indicates code 1: A problem in the Front Oxygen (02) Sensor circuit.
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Self-diagnosis Check Engine light indicates code 2: A problem in the Rear Oxygen (02) Sensor circuit.
The oxygen sensors, detects the oxygen content in the exhaust gas, and input the ECU. In operation, the ECU receives the signals from
the sensors and varies the duration during which fuel is injected. The oxygen sensors are combined with a heaters, The heaters stabilize
the sensors output. The oxygen sensors are installed in the exhaust manifolds.
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HEATER

reported on.
jumped (page 11-181,
1 (Front Oz sensor) and/or 2
(Rear 02 sensor)
dicated.
Warm up engine to normal oper-
ating temperature (cooling fan
comes on).
Run engine for 80 seconds.
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Road test with the transmission
in 4th gear, starting at 1200 rpm
accelerate using wide
throttle for at least 5 seconds.
Then decelerate for at least 5
seconds with the throttle com-
pletely closed.
Y E S
Go to page 11-38 and perform
test for CODE 43 or CODE 44.
II-30
SENSOR
TERMINAL
CODE
are in-
open
intermittent failure, system is OK
at this time. Check for poor con-
nections or loose wires at the
sensors C144, C148.
VOLTAGE (V) t
RICH + AIR-
FUEL
RATIO
02
8TOiCHiOMETRiC
AIR-FUEL RATIO
+ LEAN